Psychiatric patients and their response to experimental stress

Serum levels of Epinephrine (E), norepinephrine (NE), heart rate (HR), skin conductance reaction (SCR) and skin conductance level (SCL) were measured in schizophrenic, endogenous depressed and anxiety patients as well as in normal controls. Conditions were rest, noise and a mental arithmetic (MA) task. Schizophrenic and depressed patients had an attenuated HR response to MA. Moreover, Schizophrenic patients also had higher NE base level and the highest NE secretion during noise. Anxiety and depressed patients showed significantly lower phasic electrodermal activity (SCR) throughout the whole trial, exclusively anxiety patients had significantly higher tonic electrodermal activity (SCL). These findings indicate that autonomous reactions discriminate between patient groups and controls as well as between each other.     

Distribution of tyrosine-hydroxylase (TH)-immunoreactive neurons in the diencephalon of the pigeon (Columba livia domestica)

The distribution of tyrosine-hydroxylase (TH)-immunoreactive cell bodies and fibers in the diencephalon has been investigated with immunohistological techniques in the pigeon. The results suggest that TH is present in a number of morphologically distinct neuronal systems. Preoptic and hypothalamic TH neurons were subdivided into a medial periventricular and a lateral group. The medial group starts with a rostral collection of small cells in the preoptic region. A significantly larger collection of TH neurons occupies the paraventricular nucleus (PVN) (stratum cellulare internum) and mainly consists of large multipolar cells. Further caudally, the main concentration of cells is in the hypothalamic posteromedial and the periventricular regions of the tuberoinfundibular (arcuate) nucleus. No TH neuron was found in the ventral and lateral parts of the tuberoinfundibular region, suggesting that the prominent tuberoinfundibular dopaminergic system described in mammals is absent in the pigeon. This further substantiated by the relative scarcity of TH immunoreactive fibers and varicosities in the neurohemal zone of the median eminence (ME). The caudalmost components of the medial group appear to be continuous with the large population of TH neurons distributed in the midline of the mesencephalon. Tyrosine-hydroxylase-immunopositive cells have not been found in the paraventricular organ. The lateral group consists of TH neurons loosely arranged in the lateral hypothalamus, including regions of the supraoptic nucleus and hypothalamic posterolateral nucleus. Tyrosine-hydroxylase containing neurons vary widely in size, shape, and dendritic arborization in each diencephalic region. However, it is possible to distinguish two main cell types. Small bipolar neurons with two simple arborizing dendrites were concentrated in the medial periventricular system. The second type of cell is large, multipolar with four to five branching dendrites. This latter cell type occurs mainly in the lateral system and in the PVN. Major fiber bundles containing TH immunoreactivity were identified in the lateral and periventricular hypothalamus. The paraventricular organ and the organum vasculosum laminae terminalis contained the densest arborization of fibers and varicosities. In the ME, dense innervation was found in the subependymal layer. Dense arborizations of TH positive fibers and varicosities were located in the septal nuclei and the paleostriatum augmentatum.     

Blood pressure lowering effect of the aqueous extract of the stem of Ipomoea acanthocarpa (convolvulaceae) in spontaneously and salt-loaded hypertensive rats

Spontaneously hypertensive (SHR) and salt-loaded hypertensive rats (SLHR) were submitted to a daily treatment by gavage of 2 mL/100 g body weight of the aqueous extract of the stem of Ipomoea acanthocarpa (30 mg/mL stock solution). A fall in blood pressure of nearly 13% was observed after two successive administrations of the aqueous extract. After 14 days of treatment, the blood pressure fell by more than 30±8%. The hypotensive effect might be due to a direct vascular smooth muscle effect or to its already observed high diuretic effects or might be acting by some other mechanism.     

Haemodynamics as a determinant of the pharmacokinetics of and the plasma catecholamine responses to isoprenaline

Summary The total body clearance and fractional extraction of isoprenaline (ISO) have been determined, and the relation between these parameters and cardiac output established. Whether desipramine, an inhibitor of neuronal uptake, altered the plasma catecholamine response to ISO was also investigated.Seven healthy subjects were given i.v., infusions of ISO in two, consecutive 25-min periods, at constant dose rates of 31–43 and 80–124 pmol·kg^–1·min^–1, respectively. The total-body (ER), pulmonary (ER_p) and forearm (ER_f) fractional extractions and the total body clearance (CL) of ISO were obtained from measurements of cardiac output and the steady-state ISO concentration in mixed central venous, arterial and forearm venous plasma.ISO-induced increases in cardiac output resulted in increases in CL, decreases in ER and no consistent change in ER_f. ER_p did not differ from zero. ISO also produced a dose-dependent increase in the mixed venous plasma concentrations of noradrenaline and 3,4-dihydroxyphenylglycol (DOPEG), and a decrease in that of adrenaline. Pretreatment with desipramine did not alter any of the pharmacokinetic parameters of ISO. Desipramine, however, reduced the mixed venous baseline plasma levels of noradrenaline (47%) and DOPEG (40%), and tended to reduce that of adrenaline (34%). It enhanced the plasma noradrenaline response 2.4-fold, abolished the plasma DOPEG response and did not alter the plasma adrenaline response to ISO.Hence, owing to its haemodynamic effects, ISO modifies its own pharmacokinetics which involve non-neuronal removal processes only. The increased DOPEG in plasma resulting from the ISO-induced increase in noradrenaline release was presynaptic in origin. Desipramine appears to reduce sympathetic activity. The enhancement by desipramine of the ISO-induced increase in plasma noradrenaline points towards recapture by neuronal uptake of at least 58% of the noradrenaline released in response to ISO.     

Effect of dexfenfluramine treatment on body weight,blood pressure and noradrenergic activity in obese hypertensive patients

Summary The effect of dexfenfluramine (dF) on body weight, blood pressure and noradrenergic activity were studied in 30 obese hypertensive patients randomly divided into two groups and treated for 3 months either with dF (30 mg daily; 16 subjects) or placebo (Pl; 14 subjects). 11 patients from the dF group and 9 patients given Pl completed the entire experimental protocol, including monthly visits for metabolic and hormonal measurements, as well as a bicycle exercise test with arterial catheterisation for haemodynamic and catecholamine measurements performed before and after 3 months of treatment.A progressive significant decrease in body weight, averaging 6.0 kg after 3 months was observed in the dF-treated group, whereas loss of weight in the placebo group (1.4 kg) was not significant. While blood pressure and noradrenergic activity, assessed as changes in the plasma levels and urinary excretion of norepinephrine, remained unaffected in the Pl group, a significant drop in the supine systolic and diastolic blood pressures, as well as in the resting venous norepinephrine level and in urinary norepinephrine excretion was found after the first month of dF administration. In addition, the exercise-induced rise in systolic and diastolic blood pressure, as well as in arterial plasma norepinephrine and epinephrine concentrations, was significantly reduced after 3 months of dF administration; there were no such changes in the Pl-treated group.The results of the present study indicate that, in addition to the weight-reducing effect of dexfenfluramine, its hypotensive effect may be mediated by a decrease in noradrenergic activity.     

Influence of anaesthesia and muscle relaxation on intubating conditions and sympathoadrenal response to tracheal intubation

Background : The study aimed to assess the relative influence of anaesthesia and muscle relaxation on intubating conditions and the haemodynamic and catecholamine responses to tracheal intubation.
Methods : Sixty ASA 1 or 2 patients were randomly assigned to one of four groups (15 patients each) that differed in the depth of anaesthesia (thiopentone plus fentanyl 2.5 μg kg^-1 or thiopentone alone) and the degree of vecuronium–induced neuromuscular block (100% or _>: 65%) at intubation. Muscle relaxation was measured at 0.1 Hz by means of mechanomyography. Heart rate (HR) and mean arterial blood pressure (MAP) were measured before and after induction of anaesthesia, and 1 min and 5 min following intubation, while adrenaline (A) and noradrenaline concentrations (NA) were determined from arterial blood samples.
Results : Intubating conditions were improved primarily by providing complete muscle relaxation at the adductor pollicis muscle (P<0.001) and to a lesser extent by adding fentanyl to thiopentone (P=0.04). The response of HR and MAP to tracheal intubation was attenuated mainly by fentanyl (P<0.001). Complete muscle relaxation further diminished the response of MAP to intubation (P=0.03). Changes in A and NA were dependent on the depth of anaesthesia only (P =>0.01).
Conclusion : The results of the study demonstrate that the sympathoadrenal response to intubation is attenuated by adding fentanyl (2.5 kg^-1) to an induction regimen with thiopentone, whereas provision of complete muscle relaxation at the adductor pollicis muscle is necessary to attain smooth intubating conditions.     

Elevations of neuropeptide Y-like immunoreactivity and catecholamines in plasma on increased intracranial pressure in the pig

Graded increases of intracranial pressure (ICP) in anaesthetized pigs induced elevations of plasma levels of neuropeptide Y (NPY)-like immunoreactivity (LI) and catecholamines, simultaneously with hypertension and tachycardia. Plasma adrenaline (ADR) increased at a lower ICP-level than did the plasma levels of noradrenaline (NA) and NPY-LI. At the maximal ICP elevation, 22.9 kPa (172 mmHg), plasma NPY-LI was increased about 10-fold, from 48 +/- 8 pmol/l in the basal state, while NA and ADR concentrations increased more than 100-fold. At this maximal ICP-level the plasma levels of NPY-LI were correlated to the concentrations of both NA (r = 0.87, P less than 0.01) and ADR (r = 0.92, P less than 0.001). Plasma NPY-LI continued to increase to about 1000 pmol/l, 10 min after the maximal elevation of ICP was discontinued, while the catecholamines then had declined considerably. A slight cardiac release of NPY-LI was observed at the maximal elevation of ICP. The half-life of NPY-LI in plasma was about 6 min upon systemic infusion. At plasma levels similar to those obtained upon maximal ICP elevation, exogenous NPY caused slight vasoconstriction in the spleen and skeletal muscle, but had no effects on coronary blood flow or systemic blood pressure. This suggests that NPY mainly exerts local actions after release from nerve endings, while levels of circulating NPY in plasma must be very high to influence blood flow in some organs. It is concluded that elevation of ICP results in hypertension and tachycardia related to elevated plasma levels of NPY-LI and catecholamines.(ABSTRACT TRUNCATED AT 250 WORDS)     

急性重复性缺氧小鼠脑组织中儿茶酚胺类神经递质含量变化的研究

用高效液相-电化学检测器测定急性重复性缺氧小鼠脑组织中DOPA、DA、NE和Ep等儿茶酚胺类物质的含量。结果发现:与空白对照组(A组)比较,缺氧1次的实验对照组(B组)及急性重复缺氧4次实验组(C组),随缺氧次数增加,小鼠脑组织中的DA含量显着上升(P<0.01),NE、DOPA含量明显降低(P<0.05或<0.01);A组与急性重复4次缺氧后饲养2d的实验对照组(D组)小鼠脑组织中儿茶酚胺类含量接近,没有统计学意义(P=23.77).结果提示脑组织中儿茶酚胺类物质可能参与急性重复缺氧小鼠的耐缺氧能力的形成,而且是一个可逆的快反应。     

Thoracic epidural analgesia in aortocoronary bypass surgery II: effects on the endocrine metabolic response

Thoracic epidural analgesia (TEA) may offer haemodynamic benefits for patients with coronary heart disease going through major surgery. This may – in part – be secondary to an effect on the endocrine and metabolic response to surgery. We therefore investigated the effect of TEA on the endocrine metabolic response to aortocoronary bypass surgery (ACBS).
Thirty male patients (age < 65 years, ejection fraction > 0.5) were randomized into 3 groups; the HF group receiving a high dose fentanyl (55 μg–kg^-1) anaesthesia, the HF + TEA group with the same fentanyl dose + TEA with 10 ml bupivacain 5 mg ml^-1, followed by 4 ml every hour, and the LF + TEA group receiving fentanyl 15 μg kg^-1 + TEA. Adrenalin, noradrenalin, systemic vascular resistance (SVR), glucose, Cortisol, lactate and free fatty acids were followed during the operation and for 20 h postoperatively.
A significant increase in adrenalin, noradrenalin and SVR was found in the HF group whereas this increase was blocked in both epidural groups. An increase in glucose and Cortisol was noticed in all groups, but the increase was delayed in the epidural groups.
Our results suggest that a more effective blockade of the stress response during ACBS is obtained when TEA is added to general anaesthesia than with high dose fentanyl anaesthesia alone.     

A nonrandom interneuronal pattern in the developing frog spinal cord

In the developing spinal cord of the frog, Xenopus laevis, a population of interneurons assumes a pattern that represents a previously undescribed level of organization. Glyoxylic acid treatment and immunocytochemistry show that the neurons contain catecholamines and their synthetic enzyme, tyrosine hydroxylase. Cells are located within the ependymal layer of the floor plate region of the larval spinal cord. The cells have several processes including a long one that projects toward the brain without fasciculating with other labeled processes. In addition, the cytoplasm of the catecholaminergic cells extends into the central canal, showing that they are a population of cerebrospinal fluid-contacting neurons. The spatial domain of catecholaminergic neurons starts abruptly at the boundary between the hindbrain and spinal cord and continues to the tip of the tail. The neurons occupy two longitudinal columns within the sheet of floor plate cells, which includes cells that do not exhibit the catecholaminergic phenotype. Unlabeled cells are intercalated between catecholaminergic cells in each column, giving the labeled cells the appearance of being spaced along the length of the spinal cord. This general arrangement is evident at the time of hatching. Spatial analysis showed that the position of cells along a column is not random. The nonrandom behavior is due to cells being excluded from the area immediately surrounding other catecholaminergic cells. Further analysis showed that the cellular pattern lacks segmental or other periodic repeats. Ultimately, the location of a cell within a column depends upon the position of its closest catecholaminergic neighbor. © 1993 Wiley-Liss, Inc.