摘要:

Regional cerebral metabolic rates of glucose (rCMRglu) were measured in conscious rats grouped according to three treatments: control, bicuculline (5.5 mg/kg s.c), and intracerebroventricular arginine vasopressin (0.5 μg/5 μl). Rats in the latter group were pre-exposed to the peptide 48 h earlier to render them 100% susceptible to a motor output termed barrel rotation (BR). Marked increases in rCMRglu occurred in all brain areas investigated after bicuculline. Increases after intracerebroventricular arginine vasopressin were smaller and occurred in fewer brain areas. Opposite to bicuculline, arginine vasopressin reduced rCMRglu in hippocampus and auditory cortex. The data confirm marked stimulation of rCMRglu during bicuculline-induced seizures and provide initial data for an endogenous peptide that causes BR. Generalized seizures and BR may share some neural substrates, but they produce distinct changes in rCMRglu. The rCMRglu changes are compatible with the interpretation that BR is initiated by brainstem/cerebellar areas that process visual-vestibular information, with subsequent involvement of higher brain structure

ISSN:0031-7012    

DOI:10.1159/000138340

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Senna was introduced in therapy in the 9th century by the Arabs. In the second half of the 19th century chemical investigation of the drug was undertaken, but only a century later the sennosides were isolated.bPharmacological research on senna started at the beginning of this century. During the last 25 years interest in the pharmacology of synthetic and natural laxatives steadily increased. Senna, containing only dianthrones as active substances, is still in the center of scientific research and merits this special attention.

ISSN:0031-7012    

DOI:10.1159/000138414

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The spatial and temporal patterns of phasic contractions in the gastrointestinal tract are regulated by a complex interplay between the myogenic, neural and chemical control mechanisms. These contractions are largely responsible for the mixing and propulsive movements of the gut after a meal. In the fasted state, organized groups of contractions called cyclic motor activity and migrating motor complex keep the upper digestive tract clean of residual food and debris. In addition, the small intestine and the colon generate giant migrating contractions which are several-fold stronger than the postprandial phasic contractions and migrate uninterrupted over long distances. The giant migrating contractions are effective in rapid propulsion. The upper small intestine and the antrum generate retrograde giant contractions that generally precede vomiting.

ISSN:0031-7012    

DOI:10.1159/000138415

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The effect of esmolol on the ventricular fibrillation threshold (VFT) was determined in 11 open-chest dogs anesthetized with sodium pentobarbital. Since changes in VFT by antiarrhythmic drugs have been shown to depend on the method used to test vulnerability to fibrillation, two methods were studied. The vulnerable period was scanned with a train of pulses (100 Hz, 4 ms, 20 pulses) in nine experiments and a single pulse (10 ms) in eight experiments. Following control measurements, esmolol was administered as an intravenous bolus of 500 μg/kg followed by a continuous infusion of 300 μg/kg/min. After 15 min of infusion, the adequacy of beta-blockade was tested by the administration of 0.5 μg/kg of isoproterenol. Isoproterenol increased the heart rate by only 18 ± 2 beats/min following esmolol administration which was significantly less than the control response (79 ± 7 beats/min, p < 0.01). Although the VFT measured with the single-pulse technique did not change in response to esmolol (14.1 ± 1.1 mA vs. 14.3 ± 1.2 mA), the VFT measured with the train-of-pulses technique significantly increased (3.7 ± 0.5 mA to 14.5 ± 2.8 mA, p < 0.01). Twenty minutes after discontinuing esmolol, the VFT measurements were repeated and did not differ from control values with either technique. The increase in heart rate in response to isoproterenol also returned to control values (80 ± 6 beats/min). The results suggest that the ability of esmolol to raise VFT as measured by the train-of-pulses technique is due to beta-adrenergic blockade. The two methods may differ because of the relatively greater release of norepinephrine with the train-of-pulses

ISSN:0031-7012    

DOI:10.1159/000138341

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Several attempts have been made in order to classify the gastrointestinal motility disorders; they are mainly based upon the type of disorder in transit and the region of the gastrointestinal tract affected. Many digestive motor disturbances do not constitute entities, but are pathophysiologic mechanisms that may contribute to the production of symptoms and signs of various diseases. The abnormal interdigestive motility pattern or the migrating motor complex often corresponds to the absence of phase 3 and several observations strongly suggest that this disordered motility pattern is the cause rather than the consequence of intestinal bacterial overgrowth. Disturbances of colonic motility are often associated with diarrhea; however, the nature of motor alterations depends on the diarrheal disease (episodic, continuous with or without pain). Finally, both gastrointestinal and colonic motor disturbances may contribute to the pathogenesis of constipation and diarrhea; however, several findings suggest that colonic motor alterations are the consequence rather than the cause of changes in bowel habits.

ISSN:0031-7012    

DOI:10.1159/000138417

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The effects of the intravenously administered antidepressant drugs mianserin, imipramine, metapramine, nomifensine and amineptine against ischaemia and reperfusion arrhythmias were investigated in anaesthetized rats. Imipramine, metapramine, mianserin and high doses of nomifensine (0.5 mg·kg–1) reduced the mortality and the duration of ventricular fibrillation observed following coronary artery ligation. Amineptine was ineffective in preventing early postligation arrhythmias. With the tricyclic antidepressant drugs imipramine and metapramine, the arrhythmias were practically suppressed after 15 min following coronary artery ligation. The incidence of reperfusion arrhythmias was significantly reduced by tricyclic antidepressant drugs. In contrast, amineptine was not effective and did not alter cardiac function. It was suggested that nonspecific effects of these drugs account for their antiarrhythmic action. The most plausible explanation for their antiarrhythmic action may be a quinidine-like cardiac depressant activi

ISSN:0031-7012    

DOI:10.1159/000138342

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

Oral administration of sennosides (20–30 mg/kg) to fasted dogs has been shown to induce a strong and long-lasting inhibition of myoelectric colon activity which was evident after a delay of 6–10 h corresponding to orocecal transit and colonic metabolism and was accompanied by abundant diarrhea. When sennosides were given 1 h before a meal, the postprandial increase in colon motility failed to appear. Recent studies with strain gage transducers confirm the inhibition of colonic motility after oral sennosides but, in addition, 3–10 ‘giant contractions’ with a high amplitude appeared during the period of inhibition. Most of these single contractions were propagated over the second half of the colon at a velocity of 0.5–2 cm/min. Elimination of liquid feces was always associated with giant contractions. These giant contractions have also been described with other stimuli (i. v. guanethidine or neostigmine, oral castor oil, intraluminal hypertonic glucose) and are therefore not specific for

ISSN:0031-7012    

DOI:10.1159/000138418

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

In the presented studies, both the spontaneous motor activity and the locomotor responses to amphetamine challenge were assessed in normotensive rats and in hypertensive rats. As compared to their appropriate controls, both experimentally (either renal or deoxycorticosterone salt) hypertensive rats and spontaneously hypertensive rats maintained a higher level of spontaneous motor activity. In addition, intraperitoneal administration of amphetamine produced stimulation of forward locomotion, and head and body rearing (as shown by an increase in gross movements) and increased grooming and sniffing (as shown by an increase in fine movements). It was also found that either experimentally or spontaneously hypertensive rats displayed a greater degree of locomotor stimulant responses to amphetamine administration as compared to their appropriate controls. The results indicate that the mechanisms underlying the pathogenesis of hypertension may be related to the development of locomotor hyperactivity in rats.

ISSN:0031-7012    

DOI:10.1159/000138343

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The actions of sennosides on colonic motility are incompletely understood. We therefore studied the effects of sennosides A + B on colonic myoelectric activity and transit of a radio-opaque meal in 7 conscious cats. Intraduodenal application of sennosides (2 mg/kg body weight) accelerated the half colon transit time from 60 ± 10 (SEM) to 43 ± 7 min. At the same time the ratio of long-spike bursts to short-spike bursts was changed from 0.22 to 10.1. Loperamide, an antidiarrheal agent, had the opposite effect. The overall spike activity was not altered by sennosides, but increased by loperamide. It is concluded that the propulsive action of sennosides in the colon is reflected by myoelectric patterns and not by the total number of spike

ISSN:0031-7012    

DOI:10.1159/000138419

出版商:S. Karger AG    

年代:1988

数据来源: Karger

摘要:

The renal and pulmonary hemodynamic effects of fenoldopam, dobutamine, dopamine and norepinephrine were compared in the pentobarbital-anesthetized dog. Animals were pretreated with propranolol (1 mg/kg, i.v.) to eliminate β-adrenoceptor-mediated effects in the renal and pulmonary circulations. Heparinized blood was withdrawn from the right femoral artery and transferred, via a peristaltic pump, to the pulmonary arterial branch supplying the left diaphragmatic lobe of the lung. The flow rate of the pump was set so that the perfusion pressure in the lobe was equal to resting diastolic pulmonary artery blood pressure. Under these conditions of constant flow, changes in perfusion pressure reflect changes in pulmonary vascular resistance. Renal blood flow was measured in the same experiments via an electromagnetic flow probe which was placed directly on the left renal artery. Intraarterial administration of fenoldopam resulted in a marked reduction in renal vascular resistance at doses that had virtually no effect on pulmonary vascular resistance. Conversely, dobutamine increased pulmonary vascular resistance slightly, and had no effect on the renal circulation. Dopamine increased pulmonary vascular resistance at all doses, and exhibited a biphasic effect on renal vascular resistance. At low doses, dopamine produced a modest reduction in renal vascular resistance, and at higher doses, dopamine significantly increased renal vascular resistance. Norepinephrine increased both pulmonary and renal vascular resistance at all doses, as expected. These results indicate that fenoldopam may be hemodynamically favorable over dobutamine and dopamine in the management of patients with low output cardiac failure since fenoldopam improves renal hemodynamics at doses that have little or no effect on the pulmonary circulation

ISSN:0031-7012    

DOI:10.1159/000138344

出版商:S. Karger AG    

年代:1988

数据来源: Karger