Phenylephrine-Induced Rhythmic Activity in the Rabbit Ear Artery.

Rhythmic electrical activity in rabbit aorta induced by EGTA.

Biphasic vasoconstriction of the rabbit ear artery.

Sympathetic nerve stimulation and intralummal norepinephrine infusion for more than 15 seconds produced a biphasic response in the isolated rabbit ear artery perfused with RREBS solution. This response consisted of an initial rapid constriction (phase A), which was followed by partial relaxation, and a final slowly developing constriction (phase B), which lasted for the duration of nerve stimul...

Biphasic constrictor response of the rabbit ear artery.

The perfused rabbit ear artery shows a biphasic contractile response to intraluminal norepinephrine and sympathetic nerve stimulation. The peak of the first phase occurs after approximately 10 seconds of exposure to NE, and the second, after IK to 2 minutes. The magnitudes of the two responses are similar. The time course of the second phase of contraction is similar to the rate of saturation o...

Identification of alpha-1L adrenoceptor in rabbit ear artery.

The alpha-1L adrenoceptor (AR) was identified in rabbit ear artery by both functional and ligand binding studies. In functional studies using arterial rings, the contractile response to NS-49 [(R)-(-)-3'-(2-amino-1-hydroxyethyl)-4'-fluorometh-anesulfonanilide hydrochloride] (alpha-1A and alpha-1L AR-selective agonist) was competitively antagonized with low affinities by prazosin, RS-17053 [N-[2...

The role of endothelium in the phenylephrine-induced oscillatory responses of rabbit mesenteric arteries.

Phenylephrine-induced oscillatory contractions in rabbit mesenteric arteries were investigated in vitro. Adrenergic, cholinergic, or histamine antagonists as well as cyclooxygenase and lipoxygenase inhibitors had no effect on this phenylephrine-induced oscillation. The removal of extracellular calcium ions or treatment with a calcium antagonist reduced the amplitude and frequency of the oscilla...