腺苷及迷走神经对豚鼠心脏作用的比较研究

比较了外源性腺苷(1μmol/kg,iv)、迷走神经刺激(30 Hz,4 V,0.1 ms,10s)及缺氧(2％O_2,10 min)对豚鼠心脏(n=52)的作用,发现3者均引起窦性周期延长、房室传导时间延长及房室传导阻滞,阻滞部位都在房室结近端AH段。氨茶碱(5 mg/kg,iv)可以拮抗外源性腺苷的作用;刺激左迷走神经外周端不伴有心肌内源性腺苷含量增加;缺氧时心肌内源性腺苷含量大幅度增加,动物阿托品化(0.2mg/kg,iv)未阻断缺氧引起的心律失常及心肌腺苷含量增加。实验结果提示:高腺苷含量及高迷走神经张力均可以起窦性心率减慢及房室传导阻滞。     

梭曼对小鼠腹腔吞噬细胞的影响

用化学发光法研究了Balb/c小鼠急性梭曼中毒后腹腔吞噬细胞吞噬活性的动态变化规律。154μg/kg梭曼皮下中毒后5～15min出现典型的胆碱能中毒症状,阵发性惊厥持续6～8h,24h死亡率为46％。中毒后第1天,腹腔吞噬细胞吞噬发光峰值由对照组的26.03±3.76(10~4/10~6个细胞)降至13.22±5.92;发光均值由对照组的0.10±0.02降至0.04±0.02,吞噬活性激发时间由3.8±1.1(s)延长至8.2±1.6,均与对照组有显著差异(P<0.05)。此后,三者与全血胆碱酯酶活力平行回升,发光均者与酶活力呈正相关(r=0.550,P<0.01)。毒扁豆碱合用阿托品预防,能有效缓解梭曼对吞噬细胞活性的抑制作用。     

Salivation from the denervated human parotid gland induced by pirenzepine and telenzepine

Summary In the denervated human parotid gland the non-classical cholinolytic agents pirenzepine and telenzepine induce a similar paradoxical salivatory response to that of atropine, scopolamine and metacine.     

Double ventricular responses during extrastimulation of atrioventricular nodal reentrant tachycardia

In patients with dual atrioventricular (AV) nodal pathways,double ventricular responses to a single atrial depolarizationhave been shown to occur, but virtually only during a trialpacing in sinus rhythm. We report on a patient with a slow-fastform of AV nodal reentrant tachycardia who exhibited doubleventricular responses following extrastimulation during AV nodalreentrant tachycardia. The phenomenon of double ventricularresponses during the tachycardia was demonstrated by ex trastimulationfrom the proximal coronary sinus. Retrograde unidirectionalblock in the slow pathway, and an anterograde effective refractoryperiod that was shorter in the fast pathway than that in theslow pathway, are suggested.     

Impact of atropine injection on heart rate response during treadmill exercise echocardiography: a double-blind randomized pilot study

We evaluated the effect of atropine on the heart rate (HR) response during treadmill exercise echocardiography. A potential limitation of treadmill exercise echocardiography is the requirement for postexercise imaging. Rapid recovery of HR and wall motion abnormalities may decrease test sensitivity. A double-blind randomized study was performed at a tertiary care center. Fifty-two patients (age, 63 +/- 9 years) with known or suspected coronary artery disease were injected with either 0.5 mg of atropine or saline before treadmill exercise echocardiography. HR response during and after exercise was recorded. Atropine resulted in a greater increase in HR before exercise (increase of 15 +/- 9 vs 5 +/- 7 beats per minute, P < 0.0001) and a higher HR rate during the first 5 minutes of exercise (P < 0.05). In recovery, there was an exponential decrease in HR in both atropine and control groups. However, at the end of image acquisition (66 +/- 15 seconds), the HR was higher in the atropine group (128 +/- 21 vs 115 +/- 19 beats per minute, P = 0.02) and remained higher throughout the 10-minute recovery period (P = 0.0015). Dry mouth was more common after atropine injection (P = 0.005); other side effects were similar. The extent and resolution of myocardial ischemia were comparable in both groups. Atropine injection before treadmill exercise echocardiography results in a higher HR during the acquisition of echocardiographic images; whether atropine could affect the diagnostic accuracy of tread mill exercise echocardiography requires further study.     

Functional mechanism underlying cyclooxygenase-2 expression in rat small intestine following administration of indomethacin: relation to intestinal hypermotility

BACKGROUND AND AIM: We recently reported that cyclooxygenase (COX)-2 is upregulated in the rat small intestine after administration of indomethacin, and this may be the key to non-steroidal anti-inflammatory drug (NSAID)-induced intestinal damage. The present study investigated the mechanism for COX-2 expression induced in the rat small intestine by indomethacin, in relation with ulcerogenic processes. METHODS: Animals were given indomethacin or SC-560 p.o., and the intestinal mucosa was examined 24 h later. RESULTS: Indomethacin caused hemorrhagic lesions in the small intestine, accompanied with an increase in intestinal motility, bacterial invasion and inducible nitric oxide synthase (iNOS) activity, as well as the expression of COX-2 mRNA in the mucosa. Although SC-560 did not cause any damage, this agent caused intestinal hypermotility, the bacterial invasion and the upregulation of COX-2 expression. The mucosal PGE2 content was decreased by SC-560 at 3 h but recovered 12 h later, and this recovery of PGE2 was attenuated by both atropine and ampicillin, in addition to rofecoxib. The intestinal hypermotility response to indomethacin was prevented by both 16,16-dimethyl PGE2 and atropine, but not ampicillin. Yet all these agents inhibited not only the bacterial invasion but also the expression of COX-2 and iNOS activity in the intestinal mucosa following indomethacin treatment, resulting in the prevention of intestinal lesions. CONCLUSION: These results suggest that COX-2 expression in the intestinal mucosa following the administration of indomethacin is associated with intestinal hypermotility and bacterial invasion. The intestinal hypermotility caused by COX-1 inhibition may be a key to COX-2 expression after administration of NSAIDs and their intestinal ulcerogenic properties.     

Operational Evaluation of Three Commercial Configurations of Atropine/HI-6 Wet/Dry Autoinjectors

Commercially manufactured wet/dry autoinjectors containing atropine in solution and powdered HI-6 were evaluated using HPLC for consistency of drug delivery with various solvation times and stability of drugs postsolvation at a temperature of 40°C. Three configurations of autoinjector were tested. System A (SYS A), with a specified mixing time of 5 sec, delivered a volume of 3.0 ml containing 1.86 mg of atropine sulfate and 443 mg of the bispyridinium oxime HI-6 dichloride. System Bl (SYS Bl) and System B2 (SYS B2), with specified mixing times of 40 sec, delivered volumes of 2.3 ml containing 2.13 and 2.06 mg atropine citrate and 424 and 545 mg HI-6 dichloride, respectively. Average coefficients of variation for SYS A were 3.4% for atropine and 5.8% for HI-6 and for SYS Bl and B2 were 5.2% for atropine and 7.0% for HI-6 determinations. Stored from 3 to 14 days at 40°C after the autoinjector contents were mixed, SYS A delivered 1.77 mg atropine sulfate and SYS Bl and B2 delivered 2.02 mg atropine citrate. The delivery of HI-6 dichloride decreased with a half-life of 34 days for SYS A, 39 days for SYS Bl, and 32 days for SYS B2. This resulted in a decrease to 90% of the respective day 0 amount after 4 (SYS A) or 5 (SYS Bl or B2) days.     

Alternating Wenckebach Periods in Acute Inferior Myocardial Infarction: Clinical, Electrocardiographic, and Therapeutic Characterization

We report on twelve patients with alternating Wenckebach periods (AWP) occurring during an acute inferior myocardial infarction (AIMI). There were nine males and three females, with a mean age of 61 years (range, 43 to 75). AWP appeared during the first 48 hours of the AIMI in 10 patients and on the fourth day of hospitalization in two patients. AWP occurred spontaneously in nine patients and following the administration of atropine in the remaining three patients. Mean systolic blood pressure significantly decreased during AWP as compared to the period preceding or following the bradyarrhythmia (93 ± 42 mmHg vs 123 ± 37 mmHg, p < 0.02). Killip functional class was significantly higher during AWP as compared to the period preceding or following the bradyarrhythmia (2.1 ± 1.2 vs 1.5 ± 0.8, p < 0.02). Pacemaker therapy was initiated prophylactically in two patients, because of syncope in six, because of hemodynamic deterioration in two, and for syncope and hemodynamic deterioration in two. Three patients died in cardiogenic shock despite pacemaker therapy. No evidence of right ventricular infarction was seen in the patients.
Atropine administration during AWP significantly increased the sinus rate and significantly decreased the ventricular rates and the systolic blood pressure. In addition, three patients developed long bouts of paroxysmal AV block. Isoproterenol administration improved AV conduction in one patient, caused no change in two patients and induced non-sustained ventricular tachycardia in three patients.
In conclusion, AWP occurring during AIMI is a symptomatic bradyarrhythmia associated with hemodynamic deterioration. Drug therapy for this bradyarrhythmia is usually ineffective and sometimes paradoxical responses are observed. Pacemaker therapy is usually needed to correct symptoms and the worsening hemodynamic status. We recommend prophylactic pacemaker implantation in patients developing AWP during AIMI.     

The influence of atropine premedication on the induction of anaesthesia with isoflurane in children

Airway irritability often occurs during induction of anaesthesia with isoflurane and may be accompanied by substantial reductions in oxygen saturation. The aim of this study was to determine the influence of atropine pre-anaesthetic medication on the induction characteristics of isoflurane. The incidence and severity of airway complications were significantly reduced in children who received atropine, both the oral and intra-muscular routes being equally effective. However, almost half the children receiving no premedication had saturation levels less than 90%.