Control mechanism of smooth muscle movement of the internal anal sphincter (IAS) by enteric and extrinsic neuvous systems in the dog was investigated. Responses of IAS muscle strips to electrical field stimulation (EFS) and neurotransmitter agents were recorded in vitro. The contraction response to norepinephrine or to EFS was inhibited by phentolamine. The relaxation induced by EFS was not aff...

Crocus sativus L. (saffron) is a widely used food additive for its color and taste. The hypotensive effects of saffron have been shown in previous studies. The aim of this study was to evaluate the mechanism of vasodilatory effects induced by saffron on isolated rat aorta.To study the vasodilatory effects of saffron aqueous extract (0.5, 1 and 2 mg/mL), isolated rat thoracic aorta rings were co...

In a "physiologically sequenced" contraction (PSC), which loads the isolated muscle preparation in a manner which approximates that of the intact heart, isometric relaxation precedes isotonic relaxation and occurs at minimum ("end-systolic") length. We studied the effects of inital muscle length, load, temperature, calcium, and isoproterenol on the isometric relaxation phase of physiologically ...

MA, T. S., AND D. BOSE. Sodium in smooth muscle reluxation. Am. J. Physiol. 232(l): C59-C66, 1977 or Am. J. Physiol.: Cell Physiol. l(1): C59-C66, 1977. -The contraction of guinea-pig taenia coli due to high K+ could not be reversed by washing when Na+ was absent from the medium. Reintroduction of Na+ (7 mM or more) caused relaxation. Similar results were obtained with rat uterus. The effect of...

1. Ethylenediamine tetraacetic acid (EDTA) in low concentrations imitates all the known effects of the relaxation factor ("Marsh factor"). In extracted muscle fibers which have contracted in a solution containing adenosinetriphosphate (ATP), the addition of EBTA causes relaxation, the subsequent addition of CaCl(2), contraction. 2. In fibers which have been briefly immersed in 5 MM EDTA, ATP ca...

PURPOSE To investigate the role of endogenously generated nitric oxide (NO) in the relaxation of bovine iris sphincter. METHODS Isolated bovine sphincters were mounted on an isometric tension apparatus. Contraction-relaxation response was elicited by electrical field stimulation (ES; 12 Hz, 50-msec duration, 70-80 V). Relaxation was arbitrarily defined as maximal decrease of tension below pre...

asthma  is a clinical syndrome  characterized by chronic  airway inflammation, airway responsiveness, and expiratory airflow limitation. nocturnal symptoms and decreases in lung function are common aspects of the asthma clinical syndrome. nocturnal symptoms also appear to be associated with asthma-related mortality. in addition to its importance to the regulation of human circadian rhythms, an ...

The prevalence of asthma has taken on pandemic proportions. Since this disease predisposes patients to severe acute airway constriction, novel mechanisms capable of promoting airway smooth muscle relaxation would be clinically valuable. We have recently demonstrated that activation of endogenous airway smooth muscle GABA(A) receptors potentiates β-adrenoceptor-mediated relaxation, and molecular...

angiotensin ii is a major endocrine hormone that affects directly both vascular smooth muscle and endothelial cells. since vascular reactivity to angiotensin ii changes in more physiological and pathophysiological conditions, the present study was performed to investigate the effect of intraperitoneal administration of angiotensin-converting enzyme inhibitor and captopril (30 and 50 mg kg-1, on...

MA, T. S., AND D. BOSE. Sodium in smooth muscle reluxation. Am. J. Physiol. 232(l): C59-C66, 1977 or Am. J. Physiol.: Cell Physiol. l(1): C59-C66, 1977. -The contraction of guinea-pig taenia coli due to high K+ could not be reversed by washing when Na+ was absent from the medium. Reintroduction of Na+ (7 mM or more) caused relaxation. Similar results were obtained with rat uterus. The effect of...