The effect of indomethacin on the circulatory and plasma noradrenaline responses to cold pressor testing in normal subjects

Prostaglandins may alter neuronal noradrenaline release or vascular responsiveness to sympathoexcitation. The purpose of this study was to determine if indomethacin, a prostaglandin synthesis inhibitor, influences the sympathetic and circulatory adjustments to a commonly utilized laboratory stressor in the clinical assessment of autonomic function, the cold pressor test. Venous plasma noradrenaline levels (n = 8), mean arterial pressure and heart rate (n = 10) were measured in healthy male subjects during immersion of the non-dominant hand in cold water (1°C) for 90 s. The subjects were given either placebo or indomethacin (100 mg) in a double-blind manner. The order of administration was counterbalanced and a 1 week period was given for systemic clearance of the drug. The absolute level of mean arterial pressure was elevated during the resting control period after indomethacin treatment (88 in placebo vs. 92 mmHg in indomethacin). Both heart rate and venous plasma noradrenaline levels were similar between trials during the resting control period. Mean arterial pressure and heart rate increased similarly during cold pressor testing in both indomethacin and placebo. Venous plasma noradrenaline levels increased during cold pressor testing 162 ± 39 vs. 200 ± 69 pg/ml in indomethacin vs. placebo (p > 0.05), respectively. In addition, perceived pain (peak level = 7 ± 1 vs. 6 ± 1 units; indomethacin vs. placebo, respectively) was not different between the trials. These results suggest that administration of indomethacin in a maximal single therapeutic dose, does not affect the sympathetic nervous system or circulatory responsiveness to cold pressor testing. It may not be necessary to discontinue indomethacin prior to autonomic function testing.     

Cardiovascular adjustments and pain during repeated cold pressor test

The cold pressor test is used in the clinical testing of the autonomic nervous system. However, little is known about changes in the autonomic control of the cardiovascular system during repeated challenge with cold. Heart rate (HR), respiratory sinus arrhythmia (RSA), T-wave amplitude of ECG (TWA), blood pressure, body temperature and perceived pain were recorded in 18 male subjects during three CPTs which consisted of four minutes immersion of the left hand into cold water at 1°C. Breathing during CPT was either spontaneous or paced at 0.23 Hz or 0.1 Hz. Pain intensity and HR decreased and TWA increased during the cold immersion and in the resting period preceding cold in the second and third trials. Systolic and pulse blood pressure increased in resting periods in the third trial. RSA increased in the second and third cold challenge during paced breathing at 0.1 Hz only. A decrease in body temperature (0.48°C) at the end of the experiment correlated marginally with HR changes. Our study shows that sustained cardiovascular changes are induced by the first challenge with cold, and persist or increase with repeated cold pressor tests.     

Cyclical fluctuations in blood pressure, heart rate and cerebral blood volume in preterm infants

Many recently published papers describe cyclical changes of cerebral circulatory variables, mainly in cerebral blood flow velocity (CBFV) performed with Doppler sonography. In this paper we focus on another important variable of cerebral circulation: on cerebral blood volume (CBV) measured by near infrared spectrophotometry (NIRS). In a retrospective analysis of NIRS measurements in 20 preterm infants (median 27 3/7 weeks of gestation), the dominating frequencies and prevalence of cyclical changes of CBV and its possible correlation with peripheral circulatory variables (mean arterial pressure and heart rate) was examined. In 19 out of the 20 infants cyclical changes of CBV were found within a frequency range of 2–4.7 cycles/min which is comparable to the results of the Doppler studies describing fluctuations in CBFV. A dominating frequency of heart rate (HR), was found only in 12 out of 20 infants, and it was with 2.1–3.8 cycles/min in a similar range compared to CBV. In mean arterial blood pressure (MABP), however we detected cycles with longer periods every 1–2.5 min in 14 out of 20 infants. There was a significant coherence between MABP/CBV and HR/CBV. The area under the coherence curve, however, was significantly larger between MABP and CBV as compared to HR and CBV (P=0.0007, Wilcoxon signed-rank test).     

Influence of post-exercise activity on plasma catecholamines,blood pressure and heart rate in normal subjects

The purpose of this study was to evaluate whether or not the type of activity performed during recovery might influence the magnitude of catecholamine outflow following exercise. Six active, male volunteers between 40–52 years recovered from strenuous treadmill exercise in three different ways; standing, supine rest and walking (2 mph, 0% grade). Measurements of noradrenaline (NA), adrenaline (A), heart rate and blood pressure were made at rest, peak exercise, and at 30 s intervals through 5-min of recovery. Peak exercise NA concentrations were approximately 1000% above those recorded as rest. Early recovery was marked by a continued increase in NA from peak exercise concentrations (4614 ± 548vs. 3264 ± 485 pg/ml) which did not return to peak exercise levels until approximately 90 s of recovery. Adrenaline responses followed similar trends; however, the changes were not as sizable. Heart rate and diastolic blood pressure were significantly affected by the post-exercise condition; supine recovery produced significantly lower mean heart rates and mean diastolic blood pressures in comparison to standing or continued walking recovery conditions. Thus, these data indicate no specific recovery strategy will stem the rise in exercise-induced plasma catecholamines. Clinically, a strategy of continued walking, or better, supine recovery will best meet special clinical requirements, as well as limit the magnitude of the peak catecholamine increases.     

Effects of drugs on the autonomic control of short-term heart rate variability

The autonomic nervous system links the brain and the heart. Efferent links in the neural control of the heart consist of sympathetic and parasympathetic (vagal) fibers innervating the sinus node. Because sympathetic and vagal firing alter spontaneous sinus node depolarization, cardiac rate and rhythm convey information about autonomic influences on the heart. The easy availability of ECG rendered possible the assessment of sinus rhythm as an index of autonomic outflow. The frequency-domain approach uses non-invasive recordings and appears to provide a quantitative evaluation of the autonomic modulation of cardiovascular function. Spectral profiles resulting from vagal or sympathetic blockades at the cardiac (or vascular) level might be used as references to unravel the mechanism of action of the drug under examination. A more comprehensive assessment will be obtained if spectral analysis is used as a complement to existing techniques applied for describing the neurohumoral status of patients (microneurographic recordings, norepinephrine spillover). This review also reports some pitfalls encountered in variability studies.     

Effects of plasmapheresis on short-term variability of blood pressure in healthy donors

The acute effect of mild central hypovolaemia induced by plasmapheresis on the short-term variability of blood pressure and heart rate was evaluated in ten healthy donors. Indirect finger blood pressure was measured by a non-invasive device (Finapres). Analogue-to-digital conversion of the blood pressure was used to determine systolic, diastolic and mean blood pressure and heart rate every second. The equidistant sampling allowed a direct spectral analysis using a fast Fourier transform algorithm. Blood pressure and heart rate were maintained while an increased overall variability of blood pressure was observed after plasmapheresis. The increased total area under the curve of the systolic and diastolic blood pressure spectra was documented with the selective analysis of the three main components of the spectra: the increase in the oscillations of blood pressure following plasmapheresis predominated in the 66–129 mHz region, corresponding to Mayer waves. The spectral profile of HR was unaffected by plasmapheresis. The significant increase in the 10-s period oscillations of blood pressure after the mild central hypovolaemia could result from the unloading of cardiopulmonary (and arterial) baroreceptors which in turn could buffer the arterial pressure through sympathetic activation, detected on the systolic and diastolic pressure spectra in the low-frequency range.     

Intrathecal administration of non-NMDA receptor agonists increases arterial pressure and heart rate in the rat

We have found that spinal NMDA receptors are involved in control of sympathetic output in pathways to the heart and vessels. The present study was done to determine whether spinal non-NMDA excitatory amino acid receptors participate in cardiovascular regulation. Experiments were done on urethane-anesthetized Sprague-Dawley rats, giving the non-NMDA receptor agonists, quisqualate and kainate, and the antagonist, kynurenate, intrathecally at the spinal T9 level. Both quisqualate (30 nmol; n = 7; to activate AMPA receptors) and kainate (2 nmol; n = 6; to activate K receptors) increased arterial pressure and heart rate. The responses were characterized by a rapid onset, achieving, in most cases, greater than 80% of the maximum response within 1-4 min, and a persistence throughout the remaining 20-24 min of the experiment. I.v. injection of hexamethonium (10 mg/kg) prevented the effects of intrathecal administration of quisqualate (n = 5) but not of kainate (n = 7). To determine whether the hexamethonium-resistant effects of kainate were due to a peripheral action, kainate was given i.v. (n = 6); it was found to be without effect on arterial pressure or heart rate. The increases in arterial pressure and heart rate produced by intrathecal administration of quisqualate (30 nmol; n = 6), kainate (2 nmol; n = 6), glutamate (1 mumol; n = 6) and NMDA (2 nmol; n = 6) but not carbachol (27.4 nmol; n = 6) were prevented by similar preadministration of kynurenate (125 nmol). Intrathecal administration of kynurenate (125 nmol; n = 6; 500 nmol; n = 7) decreased arterial pressure and/or heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Both pain and EEG response to cold pressor stimulation occurs faster in fibromyalgia patients than in control subjects

Pain-evoked brain potentials elicited by laser stimulation have been repeatedly shown to be abnormal in fibromyalgia syndrome. However, to our knowledge this is the first study assessing enduring (cold pressor) pain and correlated EEG changes in fibromyalgia. EEG power and subjective pain ratings during the cold pressor test were analyzed and contrasted with tasks not involving sensory stimulation (rest, mental arithmetic and pain imagery) in 20 patients with fibromyalgia and 21 healthy control subjects. Fibromyalgia patients both perceived pain and judged pain as intolerable earlier than control subjects, while pain intensity ratings and EEG power changes during subjective awareness of pain were similar in both groups. In patients and control subjects, pain was correlated with a rise in delta, theta and beta power. EEG power spectra during pain imagery and mental arithmetic were significantly different from those observed during the cold pressor test. In conclusion, fibromyalgia patients seem to process painful stimuli abnormally in a quantitative sense, thus producing both the sensation of pain, as well as the associated EEG patterns, much earlier than control subjects. However, the quality of the pain-associated EEG changes seems similar.     

Acupuncture effects on autonomic responses to cold pressor and handgrip exercise in healthy humans

Abstract. Acupuncture at P6, Liv 3 and Li 4 attenuates the increase in blood pressure during mental stress in healthy humans. The purpose of this study was to test the hypothesis that acupuncture at these points has a generalized depressor effect seen during other stimuli to the autonomic nervous system. Thirty-eight healthy humans (mean age 33 ± 13 years) performed handgrip exercise (n = 20) or the cold pressor test (n = 18) before and after acupuncture at P6, Liv 3 and Li4. To control for repeated interventions, subjects underwent an identical protocol on a different day, during which acupuncture was replaced by quiet rest. Blood pressure and heart rate increased similarly during the first and repeat intervention (handgrip or cold pressor test). Acupuncture did not attenuate the increase in blood pressure (delta mean arterial pressure [MAP] 9.3 ± 1.8 vs 7.3 ± 3.1 mmHg) or the increase in heart rate (delta heart rate [HR] 6.7 ± 2.1 vs 6.0 ± 2.0 bpm) during handgrip exercise. Similarly, acupuncture did not attenuate the increase in blood pressure (delta mean arterial pressure [MAP] 14.8 ± 5.0 vs 14.8 ± 4.8 mmHg) or the increase in heart rate (delta heart rate [HR] 5.3 ± 2.1 vs 8.7 ± 3.6 bpm) during the cold pressor test. In summary, in normal healthy humans, acupuncture at P6, Liv 3 and Li 4 does not attenuate the blood pressure or heart rate responses during handgrip exercise or the cold pressor test.     

Effects of the converting enzyme inhibitor trandolapril on short-term variability of blood pressure in essential hypertension

Short-term fluctuations in blood pressure and heart rate were analysed in a group of eight males with essential hypertension. Indirect finger blood pressure was measured by a non-invasive device (Finapres). Analogue-to-digital conversion of the blood pressure was used to determine systolic and diastolic blood pressure and heart rate every second. The equidistant sampling allowed a direct spectral analysis using a fast Fourier transformation algorithm. The effect of 7-day administration of the angiotensin converting enzyme inhibitor, trandolapril (2 mg/day), was assessed in a double-blind, randomized, placebo-con-trolled cross-over study. After trandolapril there was a significant reduction in systolic blood pressure levels (- 15 mmHg). The reduction in diastolic blood pressure did not reach significance. The standard deviation of systolic and diastolic blood pressure levels were significantly reduced (–20% and –22% for systolic and diastolic respectively). Neither average heart rate nor standard deviations of heart rate time series was affected by the angiotensin converting enzyme inhibitor. Spectral analysis of fluctuation in blood pressure showed a reduction in the variability underlying the standard deviation changes of systolic and diastolic blood pressure. Trandolapril selectively reduced the amplitude of systolic and diastolic oscillations in the 66–129 mHz region, corresponding to Mayer waves. The significant decrease in the 10 s period oscillations of blood pressure after chronic angiotensin converting enzyme blockade with trandolapril could reflect reduced sympathetic outflow to vascular smooth muscle.     

Effects of cold exposure on autonomic changes during the last rapid eye movement sleep transition and morning blood pressure surge in humans

BackgroundVarious studies have linked the occurrence of cardiovascular events and low ambient temperatures as well as the morning blood pressure surge (MBPS). We hypothesized that low ambient temperatures produce a higher sympathetic change during the last rapid eye movement (REM) sleep transition and that this may play an important role in cold-related cardiovascular events.MethodsAll experiments were carried out on 12 healthy male adults, aged 24.00 ± 0.74 years, who participated in two experimental conditions randomly (>1 day apart): warm (23 °C) and cold (16 °C). Blood pressure (BP) was measured every 30 min for 24 h by autonomic ambulatory BP monitoring. The electroencephalograms, electrocardiograms, ambient temperature, near-body temperature, and physical activity were recorded by miniature polysomnography for 24 h.ResultsThe cold conditions resulted in: (i) higher MBPS than under warm conditions; (ii) significant and greater sympathetic index changes during the sleep–wake transition than during cover-to-uncover and supine-to-sit position tests; (iii) the non-REM–REM transition-related sympathetic elevation during the cold conditions being significantly higher in late sleep period than in early sleep period; (iv) at 1 h prior to morning awakening, the value of total power of heart rate variability changes being significantly negatively correlated with the changes of near-body temperature; and (v) significantly higher arousal index and shorter average interval of REM periods than in warm conditions.ConclusionCold exposure elevates the amplitude of MBPS and is associated with late sleep stage transition sympathetic activation, which might have important implications for cold-related cardiovascular events.     

Short-term variability of blood pressure and heart rate in hyperthyroidism

The effect of hyperthyroidism on the short-term variability of blood pressure and heart rate was evaluated in 12 untreated hyperthyroid patients during thyrotoxicosis and after a 61/2 month treatment designed to achieve a stable euthyroid state. Beat-by-beat finger blood pressure was measured with a Finapres device. The pulse interval, from which pulse rate was derived, was obtained from the blood pressure signal. Due to the significant change in heart rhythm associated with thyrotoxicosis, both pulse interval (taken as a surrogate of heart period) and pulse rate (taken as a surrogate of heart rate) were computed. Power spectral analysis showed a reduction in the overall heart period variability in the supine position in the hyperthyroid compared to the euthyroid state. This effect was observed in the low-frequency (0.005–0.068 Hz), midfrequency (0.068–0.127 Hz) and high-frequency (respiratory) domains as well, with a significant reduction of the modulus of these bands of 31%, 35% and 47%, respectively. The heart rate spectral modulus also exhibited a reduction of the high-frequency component (31%) in the supine position in the hyperthyroid subjects. These changes in heart rhythmicity corroborate a vagal deficit in hyperthyroidism. In addition, blood pressure spectral power exhibited a significant deficit in the orthostatism-induced mid-frequency systolic blood pressure rise in the hyperthyroid state (64%) compared with the euthyroid state. This observation may reflect a reduced vascular sympathetic activation with standing. The resulting vasodilatation could well contribute to normalize blood pressure in thyrotoxicosis in which cardiac output is increased.     

Global link between heart rate and blood pressure oscillations at rest and during mental arousal in normotensive and hypertensive subjects

Complex phenomena modulate the interplay between heart rate and blood pressure variability, in particular after adjustments induced by stimuli or in pathophysiological conditions. This study sought to investigate in 25 hypertensive and 16 normotensive male subjects whether relationships operating at rest may be preserved after a central nervous system arousal induced by a mental stress test. As a secondary endpoint, we evaluated the potential changes of the components of heart rate and blood pressure variability during stress. RESULTS: A significant correlation was observed between components of RR and systolic blood pressure (SBP) variability (p<0.0001), after controlling for the subject's status (normotensive vs. hypertensive) and for stress-steps (baseline condition, during stress test and recovery). Moreover, the multiple regression model accounted for the potential effects of the baseline alpha(LF) value and for the baseline heart rate and systolic blood pressure. The relationship operating between the LF/HF(RR) ratio and LF/HF(SBP) ratio was not different either at the different steps of stress test (interaction: p=0.87) or in the two groups of normotensive and hypertensive subjects (interaction: p=0.76). The variables of RR and SBP variabilities were modified during stress and recovery. In particular, the LF/HF(RR) ratio and LF/HF(SBP) ratio increased during stress and decreased during recovery. CONCLUSIONS: The association between heart rate and blood pressure oscillations was preserved during central nervous system arousal by mental stress both in normotensives and hypertensives. A central integration may account for this constant relationship, the correlation being independent from baseline heart rate, blood pressure and baroreflex sensitivity.     

Effects of an acute stressor on blood pressure and heart rate in rats pretreated with intracerebroventricular oxytocin injections

Oxytocin induces a long-lasting reduction of blood pressure in rats. The aim of the present study was to investigate the effects of an acute stressor on blood pressure and heart rate in rats previously exposed to repeated administration of intracerebroventricular (ICV) oxytocin. For this purpose oxytocin (0.3 microg, ICV) was administered to male rats once a day during 5 days. Blood pressure and heart rate were measured before and after treatment. In addition, blood pressure and heart rate were measured during 30 min after exposure to 10s of noise from an alarm clock. The oxytocin treatment reduced blood pressure significantly (systolic: 108+/-4.6 vs. 121+/-1.8, p<0.01, diastolic: 96+/-5.1 vs. 108+/-3.0, p<0.01), whereas heart rate remained unchanged. In contrast, systolic and diastolic blood pressure increased significantly after the exposure to the ringing alarm clock in the oxytocin-treated rats (p<0.05), and became equal to the blood pressure in controls. In addition, heart rate increased and stayed significantly higher in the oxytocin-treated rats compared to the controls during the 30 min observation period (ANOVA p<0.01). Twenty-four hours later, blood pressure was again significantly lower in the oxytocin-treated rats compared to controls (p<0.01). In conclusion, oxytocin decreased blood pressure without changing pulse rate. However, when the oxytocin-treated rats were subjected to the unexpected noise from a ringing alarm clock blood pressure and heart rate increased significantly. No such effect was observed in the control group. Thus repeated oxytocin treatment can, in spite of decreasing blood pressure during basal conditions, increase cardiovascular reactivity to some types of stressors.     

Depressor effect on blood pressure and flow elicited by electroacupuncture in normal subjects

To clarify the effect of electroacupuncture (Ea) on the activity of the cardiovascular system in normal individuals, hemodynamic parameters including arterial blood pressure (BP), finger blood flow (FBF) and heart rate (HR) as well as paravertebral temperature (PVT) were non-invasively recorded under Ea stimulation. Surface stimulation electrode was placed on the Hoku point (Li-4). Square wave pulses (0.05 ms) were applied from a stimulator with a stimulation frequency of 2 Hz (3 min). The stimulation intensity was five times of sensory threshold. BP and FBF were decreased (68.5+/-6.0%, P<0.01 and 96.8+/-1.1%, P<0.01 of control, respectively, n=7) while HR and PVT were increased significantly (115.0+/-5.1 of control, P<0.05 and 0.054+/-0.004 degree C, P<0.01, respectively, n=7) during Ea treatment. The results suggested an inhibition in sympathetic outflow, which induced vasodilatation of systemic arteriole and decrease in BP and FBF were elicited by Ea stimulation.     

Heart rate and heart rate variability changes in the intracarotid sodium amobarbital test

PURPOSE: Changes in heart rate and heart rate variability have been found in prior studies performed during the intracarotid sodium amobarbital (ISA) test. However, these results are not entirely consistent with current models of differential cerebral involvement in the modulation of the heart. This study was designed to re-investigate this topic with a larger N than has heretofore been used. METHODS: The electrocardiogram was recorded during left and right ISAs in 73 subjects. Raw heart rate and heart rate variability were calculated. RESULTS: Raw heart rate increased during inactivation of either hemisphere, but more so for the right hemisphere. Heart rate variability changes consistent with decreasing parasympathetic tone also were found to occur during either ISA, but to a significant degree, only during right ISA. CONCLUSIONS: The right hemisphere appears to have a greater role in cerebral regulation of cardiac function, perhaps by virtue of the modification of parasympathetic effects.     

Reproducibility of heart rate and blood pressure variability in patients with chronic obstructive pulmonary disease

Abstract. Wide variations in respiratory rate and hypoxic stimulation of chemoreceptors may produce unreliable autonomic results in patients with COPD. We studied the reproducibility of two consecutive measurements of heart rate variability (HRV) and blood pressure variability (BPV) by time frequency analysis in patients with COPD while controlling respiratory rate and oxygen hemoglobin saturation (SaO₂). Reproducibility was assessed by paired t-tests and correlation analyses between repeated measures. Correlation analyses of the log transformed low (LF) and high frequency (HF) HRV were 11.5 ± 1.1 in measurement A and 11.5 ± 1.0 in measurement B (r = 0.89, p < 0.0001), and 10.5 ± 1.1 in measurement A and 10.6 ± 1.1 in measurement B (r = 0.89, p < 0.0001) respectively. The log transformed LF and HF BPV were 4.9 ± 1.3 in measurement A and 5.3 ± 0.9 in measurement B (r = 0.70, p < 0.0002), and 6.4 ± 1.3 in measurement A and 6.6 ± 1.2 in measurement B (R = 0.71 p < 0.0001) respectively. In conclusion, time frequency analysis of HRV and BPV is reproducible and reliable in patients with COPD while controlling their respiratory rate and oxygen hemoglobin saturation. Reproducibility of these measurements may allow for a non-invasive evaluation of autonomic tone in response to treatments in COPD patients.     

Paraplegia differentially increases arterial blood pressure related cardiovascular disease risk factors in normotensive and hypertensive rats

Older individuals (>50 years of age) are increasingly sustaining spinal cord injuries (SCI) and often have pre-existing medical conditions, including hypertension. Furthermore, the life expectancy of individuals with paraplegia has increased to near that of able-bodied individuals. Thus, chronic diseases associated with aging (e.g. hypertension) are increasing in this population. We tested the hypothesis that paraplegia differentially increases blood pressure related cardiovascular disease (BP-CVD) risk factors in normotensive (Wistar Kyoto rat, WKY) and spontaneously hypertensive rats (SHR). To test this hypothesis, intact and paraplegic SHR and WKY rats were chronically instrumented for recording BP-CVD risk factors over 7 weeks. Paraplegia in both the SHR and WKY rats increased heart rates (27 and 22% in SHR and WKY, respectively), heart rate loads (425 and 323% in SHR and WKY, respectively), the standard deviation of systolic (15 and 23% in SHR and WKY, respectively) and diastolic blood pressure (15 and 13% in SHR and WKY, respectively) and reduced activity (−70 and −57% in SHR and WKY, respectively). Paraplegia in the WKY rats reduced systolic (−4%) and diastolic (−5%) blood pressures while systolic and diastolic loads were not significantly different. In sharp contrast, paraplegia in the SHR increased systolic (6%) and diastolic (5%) blood pressures as well as systolic (41%) and diastolic loads (9%). These data demonstrate that paraplegia increased BP-CVD risk factors in normotensive and hypertensive rats. Importantly, the impact of paraplegia on BP-CVD risk factors was greater in the SHR.     

利多卡因对颅内动脉瘤夹闭术后患者呛咳、血压和心率的影响

目的 观察静脉注射利多卡因对颅内动脉瘤夹闭术患者麻醉恢复期的呛咳、躁动、血压和心率的影响。方法 前瞻性选择我院2013年8月至2014年5月开颅夹闭术治疗的颅内动脉瘤患者60例,随机分为对照组和试验组,每组30例。两组患者均给予相同药物进行麻醉诱导和麻醉维持。术毕对照组静脉注射生理盐水（0.15 ml/kg）,试验组静脉注射1%利多卡因（0.15 ml/kg）。结果 术后气管导管留置期间和拔管期间,试验组患者咳嗽评分明显低于对照组（P<0.05）,试验组拔管时间、丙泊酚和佩尔地平用量均明显少于对照组（>P<0.05）。气管导管拔管后5 min内,两组收缩压、舒张压和心率均随时间变化显著下降（P<0.05）,但均高于手术结束时（>P<0.05）,且对照组明显高于试验组（>P<0.05）。>结论 静脉注射利多卡因可降低颅内动脉瘤夹闭术患者麻醉恢复期的呛咳和躁动,减少拔管期间的血压和心率波动。     

Simultaneous measurement of parasympathetic reflex vasodilator and arterial blood pressure responses in the cat

We measured the changes in lower lip blood flow and systemic arterial blood pressure evoked by lingual nerve or trigeminal spinal nucleus (Vsp) stimulation to gain an insight into the brainstem integration of sympathetic and parasympathetic responses to nociceptive stimulation. We used artificially ventilated, cervically vago-sympathectomized cats deeply anesthetized with alpha-chloralose and urethane. A lip blood flow increase occurred in an intensity- and frequency-dependent manner following electrical stimulation of Vsp or lingual nerve regardless of whether systemic arterial blood pressure increased or decreased. In contrast, there was no apparent optimal frequency for the changes in systemic arterial blood pressure elicited by electrical stimulation of Vsp or lingual nerve. No relationship was found between the amplitude of the lip blood flow increase and that of the systemic arterial blood pressure change. Microinjection of lidocaine or kainic acid into the Vsp evoked, respectively, reversible and irreversible inhibition of the lip blood flow increase and systemic arterial blood pressure change evoked by lingual nerve stimulation. When microinjected unilaterally directly into the ipsilateral Vsp, the GABA agonist muscimol abolished both lingual nerve-evoked effects (increase in lip blood flow and changes in systemic arterial blood pressure) without changing basal systemic arterial blood pressure, suggesting the presence in the Vsp of GABA receptors serving to modulate both the parasympathetically mediated lip blood flow increase and the sympathetically mediated systemic arterial blood pressure change. Lidocaine microinjection into the salivatory nucleus caused a significant attenuation of the lingual nerve-induced blood flow increase, but had no effect on the lingual nerve-induced systemic arterial blood pressure change. Thus, the neural pathway mediating the lingual nerve-induced lip blood flow increase seems to be simple, requiring a minimum of four neurons: trigeminal afferent-Vsp-parasympathetic pre-ganglionic neurons with cell body located in the inferior salivatory nucleus-otic postganglionic neuron. On the other hand, the pathway underlying the evoked systemic arterial blood pressure changes, presumably mediated via altered sympathetic activity, seems to be more complicated and could be affected by more numerous factors.