title: Epinephrine release and presynaptic alpha 2-adrenoceptic regulation in the guinea pig hypothalamus.
abstract: The release of epinephrine (E) and its regulation system were investigated in the slices of guinea pig hypothalamus. Electrical stimulation produced an efflux of [3H]E from tissues preloaded with [3H]E, in a current- and frequency-dependent manner. Stimulated [3H]E release was inhibited by tetrodotoxin and by a calcium-free medium containing ethylene glycol bis(beta-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA). Stimulated [3H]E release was enhanced by yohimbine and this effect was suppressed by clonidine. These results provide strong evidence for the neurotransmitter role of E in the hypothalamus, and suggest the possible existence of regulatory mechanism of E release via presynaptic alpha 2-receptors.
authors.forename: Y
authors.initials: Y
authors.lastname: Fujii
authors.forename: H
authors.initials: H
authors.lastname: Fujiwara
authors.forename: C
authors.initials: C
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D004837:Epinephrine / Q000032:analysis / Q000502:physiology*; D006168:Guinea Pigs; D007031:Hypothalamus / Q000032:analysis / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D009435:Synaptic Transmission; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D003000:Clonidine; D004837:Epinephrine