Increased reactivity of murine mesenteric veins to adrenergic agonists: functional evidence supporting increased alpha1-adrenoceptor reserve in veins compared with arteries.

Increased Reactivity of Murine Mesenteric Veins to Adrenergic Agonists: Functional Evidence Supporting Increased Alpha-1 Adrenoceptor Reserve in Veins Compared to Arteries

Phenylpropanolamine constricts mouse and human blood vessels by preferentially activating alpha2-adrenoceptors.

Phenylpropanolamine (dl-norephedrine) was one of the most widely used therapeutic agents to act on the sympathetic nervous system. Because of concerns regarding incidents of stroke, its use as a nasal decongestant was discontinued. Although considered an alpha1-adrenergic agonist, the vascular adrenergic pharmacology of phenylpropanolamine was not fully characterized. Unlike most other circulat...

Differential localization of P2 receptor subtypes in mesenteric arteries and veins of normotensive and hypertensive rats.

ATP acts at P2 receptors to contract blood vessels and reactivity to vasoconstrictor agents is often altered in hypertension. This study was designed to identify P2 receptors in mesenteric arteries and veins and to determine whether ATP reactivity is altered in deoxycorticosterone acetate (DOCA)-salt hypertensive rats. Computer-assisted video microscopy was used to measure vessel diameter in vi...

Impaired function of alpha2-adrenergic autoreceptors on sympathetic nerves associated with mesenteric arteries and veins in DOCA-salt hypertension.

The present study tested the hypothesis that there is impaired function of alpha(2)-adrenergic autoreceptors and increased transmitter release from sympathetic nerves associated with mesenteric arteries and veins from DOCA-salt rats. High-performance liquid chromatography was used to measure the overflow of ATP and norepinephrine (NE) from electrically stimulated mesenteric artery and vein prep...

Effects of Alpha-Adrenoceptor Agonists and Antagonists on Pial Veins of Cats

Cerebral blood volume and intracranial pressure may be modified by influences on cerebral veins. The known adrenergic innervation of cerebral veins and their sensitivity to norepinephrine raised the question, whether pial veins can be selectively influenced through adrenoceptors in vivo. Therefore, alpha] and alpha2 adrenoceptor agonists and antagonists were locally injected into the perivascul...