Feeding Elicited by α and β Adrenoceptor Agonists Injected Intrahypothalamically in Sheep
| Autor: | J.M. Forbes, J.S. Beyea, C.W. Simpson, F.H. Martin, Clifton A. Baile |
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| Rok vydání: | 1974 |
| Předmět: |
Male
Agonist medicine.medical_specialty Epinephrine Adrenergic receptor medicine.drug_class Hypothalamus Neurotransmission Biology Injections β adrenoceptor Eating Norepinephrine chemistry.chemical_compound Internal medicine Methods Genetics medicine Animals Albuterol Phentolamine Neurotransmitter Practolol Adrenergic alpha-Antagonists Sheep Phenoxybenzamine Isoproterenol Antagonist Animal Feed Endocrinology chemistry Salbutamol Animal Science and Zoology Procaine Food Science medicine.drug |
| Zdroj: | Journal of Dairy Science. 57:68-80 |
| ISSN: | 0022-0302 |
| DOI: | 10.3168/jds.s0022-0302(74)84833-2 |
| Popis: | The possible role of a putative hypothalamic neurotransmitter system, adrenoceptors, in control of feed intake was studied in sheep. Sheep were surgically prepared with medial, anterior, and lateral hypothalamic guides. Medial and anterior hypothalamic loci were found in which 1-norepinephrine, an α adrenoceptor agonist, elicited feeding; 240 nmol resulted in the most feeding in a dose-response test. Intrahypothalamically injected dl-isoproterenol, a β adrenoceptor agonist, also elicited feeding, and 4 to 8 nmol resulted in maximal responses. Although loci which gave maximal responses to 1-norepinephrine were different from those giving maximal responses to dl-isoproterenol in an individual sheep, neither type of locus was restricted to one hypothalamic area. Neither α nor β antagonists affected feeding when injected alone into loci showing either α or β agonist elicited feeding. However, the antagonists blocked the feeding elicited by their respective agonist. Injections of an α or a β agonist over a wide range of doses into lateral hypothalamic areas did not affect feeding. In medial hypothalamic loci in which 1-norepinephrine elicited feeding, 1-epinephrine, an adrenoceptor agonist with both α and β adrenergic activity, elicited feeding when doses of 7.5 (like dl-isoproterenol) or 240 nmoles (like 1-norepinephrine) were injected. Feeding which was elicited by injections of a selective β adrenoceptor agonist, salbutamol ( β 2 ), was blocked by a selective β antagonist, practolol. Both α and β adrenoceptors may be involved in the neurotransmission of signals which can elicit feeding in sheep, but the apparent β adrenoceptors cannot be characterized as either β 1 or β 2 . |
| Databáze: | OpenAIRE |
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