Effects of the application of alpha 1- and alpha 2-adrenoceptor agonists and antagonists into the ventromedial hypothalamus on the sodium and potassium renal excretion.
The effects of sodium and potassium excretion after intrahypothalamic administration of two alpha-adrenoceptor agonists and the effect of alpha-adrenoceptor antagonists were studied in groups of rats. Prazosin was equally effective at blocking the natriuretic and kaliuretic responses to the alpha 1-adrenoceptor agonist phenylephrine and the mixed alpha 1/alpha 2-adrenoceptor agonist noradrenaline, while yohimbine which acts preferentially on alpha 2-adrenoceptors was effective in potentiating these responses. These results suggest the presence of two types of alpha-adrenoceptors for the modulation of ventromedial hypothalamic pathways that interfere with the regulation of the two cations: stimulation of alpha 1-adrenoceptors facilitates, while stimulation of alpha 2-adrenoceptors inhibits the excretion of the ions.
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D007033:Hypothalamus, Middle / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D011188:Potassium / Q000652:urine*; D011224:Prazosin / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D012964:Sodium / Q000652:urine*; D015016:Yohimbine / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D010656:Phenylephrine; D015016:Yohimbine; D012964:Sodium; D011188:Potassium; D009638:Norepinephrine; D011224:Prazosin