title: Alpha-adrenergic pathways in the lateral hypothalamus are important for the dipsogenic effect of carbachol injected into the medial septal area.
abstract: We studied the effect of the alpha 1- and alpha 2-adrenergic receptors of the lateral hypothalamus (LH) on the control of water intake induced by injection of carbachol into the medial septal area (MSA) of adult male Holtzman rats (250-300 g) implanted with chronic stainless steel cannulae into the LH and MSA. The volume of injection was always 1 microliter and was injected over a period of 30-60 s. For control, 0.15 M NaCl was used. Clonidine (20 nmol) but not phenylephrine (160 nmol) injected into the LH inhibited water intake induced by injection of carbachol (2 nmol) into the MSA, from 5.4 +/- 1.2 ml/h to 0.3 +/- 0.1 and 3.0 +/- 0.9 ml/h, respectively (N = 26). When we injected yohimbine (80 nmol) + clonidine (20 nmol) and prazosin (40 nmol) + clonidine (20 nmol) into the LH, water intake induced by injection of carbachol into the MSA was inhibited from 5.4 +/- 1.2 ml/h to 0.8 +/- 0.5 and 0.3 +/- 0.2 ml/h, respectively (N = 19). Water intake induced by carbachol (2 nmol) injected into the MSA was decreased by previous injection of yohimbine (80 nmol) + phenylephrine (160 nmol) and prazosin (40 nmol) + phenylephrine (160 nmol) from 5.4 +/- 1.2 ml/h to 1.0 +/- 0.7 and 1.8 +/- 0.8 ml/h, respectively (N = 16). The cannula reached both the medial septal area in its medial portion and the lateral hypothalamus. It has been suggested that the different pathways for induction of drinking converge on a final common pathway.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Departamento de Ciências Fisológicas, Faculdade de Odontologia, Universidade Estadual Paulista, Araraquara, Brasil.
authors.forename: J C
authors.initials: JC
authors.lastname: Callera
authors.forename: W A
authors.initials: WA
authors.lastname: Saad
authors.forename: L A
authors.initials: LA
authors.lastname: Camargo
authors.forename: J V
authors.initials: JV
authors.lastname: Menani
authors.forename: A
authors.initials: A
authors.lastname: Renzi
authors.forename: W
authors.initials: W
authors.lastname: Abrão-Saad
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D003000:Clonidine / Q000494:pharmacology; D004326:Drinking / Q000187:drug effects*; D007026:Hypothalamic Area, Lateral / Q000187:drug effects*; D008297:Male; D010656:Phenylephrine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D011950:Receptors, Cholinergic / Q000187:drug effects*; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D011942:Receptors, Adrenergic, alpha; D011950:Receptors, Cholinergic; D010656:Phenylephrine; D015016:Yohimbine; D002217:Carbachol; D003000:Clonidine; D011224:Prazosin