title: Epinephrine-stimulated maintained rubidium efflux from guinea pig hepatocytes may involve alpha 1- and alpha 2-adrenoceptors.
abstract: The epinephrine-stimulated maintained increase in 86Rb efflux from guinea pig hepatocytes may consist of both alpha 1- and alpha 2-adrenoceptor-mediated components. Both the alpha 1-selective adrenoceptor agonist phenylephrine and the alpha 2-selective agonist clonidine evoked a maintained increase in 86Rb efflux. Prazosin, an alpha 1-selective antagonist, did not inhibit the maintained increase in 86Rb efflux elicited by epinephrine, whereas yohimbine, an alpha 2-selective antagonist, did. In the absence of external Ca, no maintained increase in 86Rb efflux was observed. The results suggest that there may be two separate alpha-adrenergic sensitive Ca influx pathways into guinea pig hepatocytes, one mediated by alpha 1- and the other by alpha 2-adrenoceptor activation.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D003000:Clonidine / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism*; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D012413:Rubidium / Q000378:metabolism*; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D011942:Receptors, Adrenergic, alpha; D010656:Phenylephrine; D015016:Yohimbine; D012413:Rubidium; D003000:Clonidine; D002118:Calcium; D011224:Prazosin; D004837:Epinephrine