Depolarizing effect of noradrenaline on neurons of the rat supraoptic nucleus in vitro.
Noradrenaline (NA) (1-100 microM) was applied to 41 neurons recorded intracellularly from the supraoptic nucleus (SON) of the rat hypothalamic slice preparation; 34 (83%) neurons showed membrane depolarization which was dose-dependent. The depolarization was frequently accompanied by decreased membrane resistance, increased firing rate and increased fluctuations in membrane potential. Following the application of the alpha-agonist, phenylephrine, 10 out of 11 neurons tested showed similar responses, while the beta-agonist, isoproterenol, caused no changes in 6 out of 7 SON cells. We found no difference in responsiveness between neurons having a 'phasic' or a 'non-phasic' pattern of firing. We conclude that NA depolarized and increased the firing rate of both vasopressin- and oxytocin-containing neurons through an action on alpha-adrenergic receptors.
D000818:Animals; D005071:Evoked Potentials / Q000187:drug effects; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology*; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000187:drug effects; D013495:Supraoptic Nucleus / Q000187:drug effects* / Q000502:physiology
D011941:Receptors, Adrenergic; D010656:Phenylephrine; D007545:Isoproterenol; D009638:Norepinephrine