Thirty-eight healthy women undergoing elective Caesarean section under spinal anaesthesia at term were allocated randomly to receive boluses of either phenylephrine 100 micrograms or ephedrine 5 mg for maintenance of maternal arterial pressure. The indication for administration of vasopressor was a reduction in systolic pressure to < or = 90% of baseline values. Maternal arterial pressure (BP) ...

Background: In most of the obstetric patients undergoing caesarean section, spinal anaesthesia is the most accepted approach. It provides a rapid, intense, definite and better sensory and motor blockade. In spite of this, eighty per cent of patients experience hypotension after spinal anaesthesia. The use of vasopressors (Phenylephrine and Ephedrine) is the mainstay of treatment for hypotension...

The phasic contraction to phenylephrine of the rat isolated portal vein was investigated using functional studies. Phasic contractions to phenylephrine and caffeine could be produced after several minutes in Ca(2+)-free Krebs solution, which were inhibited by cyclopiazonic acid or ryanodine. The phenylephrine and caffeine contractions were abolished, however, within 10 min in Ca(2+)-free Krebs ...

Hyperhomocysteinemia is a known risk factor for cardiovascular diseases, but the underlying mechanisms of this pathology are complex. We aimed to evaluate the effect of hyperhomocysteinemia in vasorelaxations induced by alpha(1D)-adrenoceptor agonists. Vascular reactivity of rat carotid artery to the alpha-adrenoceptor agonist, phenylephrine, was enhanced in hyperhomocysteinemia. Mechanical rem...

OBJECTIVE To observe if phenylephrine mixed with propofol can attenuate hypotensive effects of propofol during induction of anaesthesia. METHODS A total number of 135 adult ASA-I and ASA-II patients were divided into three groups. (Group A, B and C). All patients were induced with propofol 2.5 mg per kg. In Group A (control group) patients received propofol mixed with 2cc of 0.9% normal salin...

Clonidine is a classically categorized α2-adrenoceptor (α2-AR) agonist that produces vascular contractions by stimulating arterial smooth muscle α2-ARs. However, clonidine inhibits α1-AR-mediated arterial contractions. Recently, it was suggested that repeated stimulation with clonidine induces desensitization of α2-ARs, thus inhibiting noradrenaline-induced smooth muscle contractions. In the pr...

Burt, Richard P. Phasic contractions of the rat portal vein depend on intracellular Ca2 release stimulated by depolarization. Am J Physiol Heart Circ Physiol 284: H1808–H1817, 2003; 10.1152/ajpheart.00637.2002.—The phasic contraction to phenylephrine of the rat isolated portal vein was investigated using functional studies. Phasic contractions to phenylephrine and caffeine could be produced aft...

BACKGROUND During spinal anesthesia for cesarean delivery, phenylephrine can cause reflexive decreases in maternal heart rate and cardiac output. Norepinephrine has weak β-adrenergic receptor agonist activity in addition to potent α-adrenergic receptor activity and therefore may be suitable for maintaining blood pressure with less negative effects on heart rate and cardiac output compared with ...

The aim of this study was to see whether increased activity of nitric oxide (NO) might account for decreased pulmonary vascular tone seen in the hyperdynamic circulation of cirrhosis. We compared the pulmonary vascular reactivity of isolated pulmonary arteries (PA) from control rats (n = 10), and rats with biliary cirrhosis (n = 10) induced by chronic bile duct ligation (4 weeks). The responses...

H P HE RATIONALE for using the vasocon••strictor agent phenylephrine to revert paroxysmal auricular tachycardia was that it would be expected to elicit cardioinhibitory reflexes from the rise in pressure in the carotid sinuses and aortic arch." However, Keys and Violante suggested the possibility that phenylephrine "produces a primary bradycardia by inhibition of the sinoauricular node and this...