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Responses of rostral hypothalamic neurones to peripheral temperature and to amines
Author(s) -
Jell Ralph M.
Publication year - 1974
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1974.sp010611
Subject(s) - amine gas treating , acetylcholine , biogenic amine , cats , iontophoresis , stimulation , peripheral , chemistry , microinjection , biophysics , hypothalamus , endocrinology , medicine , neuroscience , biology , central nervous system , neurotransmitter , organic chemistry
1. Five‐barrelled micropipettes have been used to record extracellularly the activity of neurones in the rostro‐medial hypothalamus of methoxyflurane‐anaesthetized cats, and to apply acetylcholine (ACh), noradrenaline (NA) and 5‐hydroxytryptamine (5‐HT) by micro‐iontophoresis to the vicinity of each neurone encountered. Peripheral thermal stimulation was achieved by blowing warm (42° C) and cold (4° C) air in the face of the animal, and thermoresponsiveness was compared with amine responsiveness. 2. One hundred and twenty‐two neurones were obtained from ten cats. Eleven (9%) were warm‐responsive and sixteen (13%) were cold‐responsive. The rest did not respond to facial warming or cooling. 3. No consistent relationship was observed between amine responses and responsiveness to facial temperature. Warm‐responsive neurones were mainly depressed or unaffected by amines. Cool‐responsive neurones were excited, depressed or unaffected by amines with the exception that no 5‐HT excitations were seen. Thermoresponsive neurones were more likely to be amine depressed than non‐thermoresponsive neurones. 4. Six thermoresponsive neurones responded to peripheral temperature and to amines in a way which fitted the amine model of Myers (1971). Fifteen thermoresponsive neurones fitted the model of Bligh, Cottle & Maskrey (1971), according to the same criteria. 5. The results lend little support to the amine model, as predicted from amine micro‐injection and release studies in primates, but support more strongly the model of Bligh et al. (1971) which is based on intraventricular injections of amines in sheep, goats and rabbits. On the basis of the latter model, functional identification was possible in 63% of the thermoresponsive rostral hypothalamic neurones tested.