The nonselective alpha-adrenergic agonist oxymetazoline inhibits parathyroid hormone (PTH)-stimulated cAMP production in intact OK cells, an epithelial cell line derived from an American opossum kidney. This inhibition, however, is not blocked by alpha 2-adrenergic receptor antagonists. After excluding several alternate hypotheses to explain this anomalous activity of oxymetazoline, we hypothes...

We have examined the interaction between muscarinic and alpha(2)-adrenergic receptor activation on inositol phosphate (IP) formation in the nonpigmented cells of the ciliary body epithelium (NPE cells) of the rabbit. We have compared these changes with those previously observed in the intracellular free Ca(2+) concentration. Whereas muscarinic receptor activation causes an increase in intracell...

Results from recent studies have shown that alpha(1A)-adrenergic receptor (alpha(1A)-AR) antagonists could offer a new alternative in the treatment of preterm delivery. However, members of this group [2-(2,6-dimethoxyphenoxyethyl)aminomethyl-1,4-benzodioxane hydrochloride (WB4101), 5-methylurapidil (5-MU)] are known to influence serotonin (5-hydroxy-tryptamine) (5-HT(1A)) receptors, too. Our ob...

We investigated the effects of restraint and footshock stress and norepinephrine treatment on gastric emptying. The gastric emptying was significantly inhibited by restraint stress. beta(3)-adrenergic antagonist canceled the inhibition of gastric emptying caused by restraint stress, while beta(1)-, beta(2)-, alpha(1)-, and alpha(2)-adrenergic antagonists did not affect the inhibition. Norepinep...

Prazosin, an antagonist of alpha 1-adrenergic receptors, has been found to suppress the clinical and histological expression of experimental autoimmune encephalomyelitis (EAE) in the Lewis rat. Suppression was more significant in females than in males and was a dose-dependent phenomenon. Analysis of the effect of other adrenergic receptor antagonists supports the conclusion that the suppressive...

Painful hypersensitivity to norepinephrine (NE) has been reported in various chronic pain conditions that exhibit sympathetically-maintained pain (SMP), particularly CRPS-I and II. We investigated the parallels between the nociceptive and vascular sensitivity to NE in rats with chronic post-ischemia pain (CPIP), an animal model of CRPS-I induced by hind paw ischemia-reperfusion injury. Intrader...

The purpose of this study was to determine whether both alpha 1- and alpha 2-adrenergic receptors exist on vascular smooth muscle of microvessels and whether adrenergic constriction of anatomically distinct microvascular segments is differentially subserved by either receptor subtype. The cremaster skeletal muscle of anesthetized rats was acutely denervated and suspended in a Krebs bath contain...

Activity against the coccidial pathogen Eimeria tenella in chickens has been discovered among alpha 2 adrenergic agonists. The clonidine analog 7-bromo-N-(2-imidazolidinylidene)-1H-indazol-6-amine was active in feed at 7.5 ppm, a concentration similar to the use levels of potent commercial agents, e.g., maduramicin. Additional alpha 2 agonists were also found to have anticoccidial activity, for...