Noradrenergic excitatory inputs to median preoptic neurones in rats.
Extracellular single-unit activity was recorded from 21 median preoptic nucleus (MnPO) neurones, antidromically identified as projecting to the hypothalamic paraventricular nucleus (PVN), in urethane-anaesthetized male rats. Of these identified MnPO neurones, 14 displayed an excitatory response in neuronal excitability following electrical stimulation (5 Hz, 600 microA) of the A1 noradrenergic region of the ventrolateral medulla, while the remaining neurones were unresponsive. The excitatory response of MnPO neurones was blocked by microiontophoretically applied phentolamine, an alpha-adrenoceptor antagonist, but not by timolol, a beta-adrenoceptor antagonist. These results suggest that the A1 region acts to enhance the activity of MnPO neurones projecting to the PVN via an alpha-adrenoceptor mechanism.
Tanaka
J
J
Department of Physiology, Saitama Medical School, Japan.
Nishimura
J
J
Kimura
F
F
Nomura
M
M
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D007478:Iontophoresis; D008297:Male; D008839:Microelectrodes; D009434:Neural Pathways / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects*; D009638:Norepinephrine / Q000502:physiology*; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology* / Q000187:drug effects; D011301:Preoptic Area / Q000166:cytology* / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D011941:Receptors, Adrenergic / Q000187:drug effects; D013194:Staining and Labeling
D000317:Adrenergic alpha-Antagonists; D000319:Adrenergic beta-Antagonists; D011941:Receptors, Adrenergic; D009638:Norepinephrine