title: Sodium intake combining cholinergic activation and noradrenaline into the lateral parabrachial nucleus.
abstract: The administration of cholinergic agonists like pilocarpine intraperitoneally (i.p.) or carbachol intracerebroventricularly (i.c.v.) induces water, but non significant hypertonic NaCl intake. These treatments also produce pressor responses, which may inhibit sodium intake. Noradrenaline (NOR) acting on α2-adrenoceptors in the lateral parabrachial nucleus (LPBN) deactivates inhibitory mechanisms increasing fluid depletion-induced sodium intake. In the present study, we investigated: (1) water and 1.8% NaCl intake in rats treated with pilocarpine i.p. or carbachol i.c.v. combined with NOR into the LPBN; (2) if inhibitory signals from cardiovascular receptors are blocked by NOR in the LPBN. Male Holtzman rats with stainless steel guide-cannulas implanted in the lateral ventricle and bilaterally in the LPBN were used. Bilateral injections of NOR (80nmol/0.2μl) into the LPBN decreased water intake (0.8±0.3, vs. saline (SAL): 2.9±0.3ml/180min) induced by pilocarpine (1mg/kg of body weight) i.p., without changing 1.8% NaCl intake (0.8±2.4, vs. SAL: 0.5±0.3ml/180min). Prazosin (1mg/kg of body weight) i.p. blocked pressor responses and increased water and 1.8% NaCl intake (6.3±1.7 and 14.7±3.5ml/180min, respectively) in rats treated with pilocarpine combined with NOR into the LPBN. Prazosin i.p. also increased 1.8% NaCl intake in rats treated with carbachol i.c.v combined with NOR into the LPBN. The results suggest that different signals inhibit sodium intake in rats treated with cholinergic agonists, among them those produced by increases of arterial pressure that are not efficiently deactivated by NOR acting in the LPBN.
authors.affiliation: Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil.
authors.forename: S
authors.initials: S
authors.lastname: Gasparini
authors.affiliation: Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil.
authors.forename: G M F
authors.initials: GM
authors.lastname: Andrade-Franzé
authors.affiliation: Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil.
authors.forename: J M C
authors.initials: JM
authors.lastname: Gomide
authors.affiliation: Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil.
authors.forename: C A F
authors.initials: CA
authors.lastname: Andrade
authors.affiliation: Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil.
authors.forename: L A
authors.initials: LA
authors.lastname: De Luca
authors.affiliation: Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil.
authors.forename: D S A
authors.initials: DS
authors.lastname: Colombari
authors.affiliation: Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil.
authors.forename: P M
authors.initials: PM
authors.lastname: De Paula
authors.affiliation: Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Colombari
authors.affiliation: Department of Physiology and Pathology, School of Dentistry, São Paulo State University, UNESP, Araraquara, SP, Brazil. Electronic address: menani@foar.unesp.br.
authors.forename: J V
authors.initials: JV
authors.lastname: Menani
mesh_terms: D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002217:Carbachol / Q000494:pharmacology; D002408:Catheters, Indwelling; D018679:Cholinergic Agonists / Q000494:pharmacology*; D004326:Drinking / Q000187:drug effects / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*; D065823:Parabrachial Nucleus / Q000187:drug effects / Q000378:metabolism*; D010862:Pilocarpine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D017207:Rats, Sprague-Dawley; D017673:Sodium Chloride, Dietary
chemical_list: D000959:Antihypertensive Agents; D018679:Cholinergic Agonists; D017673:Sodium Chloride, Dietary; D010862:Pilocarpine; D002217:Carbachol; D009638:Norepinephrine; D011224:Prazosin
keywords: baro and volume receptors; blood pressure; parabrachial nucleus; sodium appetite; α(2) adrenoceptors