We have investigated the effects of isoflurane on receptor-operated Ca2+ channels (ROC) in vascular smooth muscle. In isolated rat thoracic aortic rings denuded of endothelium, the effects of isoflurane on phenylephrine-induced contraction and Ca2+ influx were evaluated in the presence of supramaximal doses of nifedipine or verapamil. Under isometric tension recording, the aortic rings were pre...

BACKGROUND Phenylephrine use has been recommended over ephedrine for the management of hypotension after spinal anesthesia for elective caesarean section. The evidence for this is rather limited because in previous trials, pH was significantly lower after ephedrine, but absolute values were still within normal range. We pooled the available data to define maternal and neonatal effects of the tw...

OBJECTIVE To determine whether matrine, a kind of traditional Chinese medicinal alkaloid, can relax the aortic smooth muscles isolated from guinea pigs and to investigate the mechanism of its relaxant effects. METHODS Phenylephrine or potassium chloride concentration-dependent relaxation response of aortic smooth muscles to matrine was studied in the precontracted guinea pigs. RESULTS Matri...

OBJECTIVE To reduce vascularisation before surgery through the application of topical vasoconstrictors, decreases the rate of intraoperative bleeding, improves the dynamics of the surgery and reduces the difficulty in surgical performance. METHODS Only patients with primary pterygium were included in the study. A prospective randomized clinical trial was designed to compare intraoperative ble...

BACKGROUND Cutaneous autonomic function can be quantified by the assessment of sudomotor and vasomotor responses. Although piloerector muscles are innervated by the sympathetic nervous system, there are at present no methods to quantify pilomotor function. OBJECTIVE To quantify piloerection using phenylephrine hydrochloride in humans. DESIGN Pilot study. SETTING Hospital-based study. PA...

The involvement of catecholamines in stress-induced heart injury is well documented. However, the contribution of adrenergic receptor types is less understood. Both the profile of plasma marker enzyme activities (lactate dehydrogenase-1 and aspartate transaminase) and the distribution and morphology of the lesions observed in tissue sections of adrenaline-injected mice resembled those of stress...

Purpose: To evaluate and compare the effect of topical mydriatic eye drops (0.5% tropicamide alone, and a 0.5% tropicamide/0.5% phenylephrine mixture) on the retinal perfusion using optic coherence tomography angiography (OCTA). Methods: The perfused vessel density in the macular and peripapillary areas of both eyes was measured in eight healthy subjects using OCTA and a split-spectrum amplitud...

The release of [3H]norepinephrine from isolated mouse vas deferens has been measured. 1-Phenylephrine and 1-norepinephrine significantly enhanced the spontaneous release of radioactivity. As shown by a combination of HPLC and scintillation spectrometry, the release of total radioactivity in response to 1-phenylephrine or 1-norepinephrine consisted mainly of [3H]norepinephrine. Evidence has been...

During development, there are changes in the response of automatic cardiac fibers to alpha-adrenergic agonists. In neonatal rat ventricle, in vitro phenylephrine (1 X 10(-8) M) induces an increase in automatic rate from 115 +/- 12 (mean +/- SEM) to 168 +/- 10 beats/min, P less than 0.05. In contrast, in adult rat ventricle, the rate decreases from 36 +/- 8 to 12 +/- 12 beats/min, P less than 0....