title: Involvement of the median preoptic nucleus in blood pressure control.
abstract: Studies have demonstrated that median preoptic nucleus (MnPO) neurons play a role in organizing the cardiovascular responses induced by changes in the circulating blood volume. The present study examined whether the MnPO controls cardiovascular function. Male Wistar normotensive (NT) rats and spontaneously hypertensive rats (SHRs; 250-300 g) were anesthetized with urethane (1.2 g kg(-1), i.v.) and instrumented for recordings of mean arterial blood pressure (MAP) and renal blood flow (RBF). The renal vascular conductance (RVC) was calculated as the RBF:MAP ratio and was expressed as a percentage of the baseline value. In the NT rats (n=6), MnPO inhibition produced a MAP reduction (-8.1±1.1 mmHg, p<0.05). In the SHRs (n=6), the MAP response to MnPO inhibition was significantly greater (-22.3±4 mmHg, p<0.05) than in the NT rats. Furthermore, the increase in the RVC was higher in the SHRs (10.9±3.3%, p<0.05). Histological analyses confirmed that the injection sites were confined to the MnPO. We conclude that the MnPO is involved in the tonic regulation of blood pressure in NT rats. Moreover, the greater cardiovascular response to MnPO inhibition observed in the SHRs strongly suggests that the MnPO may contribute to the pathophysiology of essential hypertension.
authors.affiliation: Center for Neuroscience and Cardiovascular Physiology, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goiás, GO, Brazil.
authors.forename: Ludmila
authors.initials: L
authors.lastname: de Lima Silveira
authors.affiliation: Center for Neuroscience and Cardiovascular Physiology, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goiás, GO, Brazil.
authors.forename: Elaine Fernanda
authors.initials: EF
authors.lastname: da Silva
authors.affiliation: Center for Neuroscience and Cardiovascular Physiology, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goiás, GO, Brazil.
authors.forename: Aline Mourão
authors.initials: AM
authors.lastname: de Andrade
authors.affiliation: Center for Neuroscience and Cardiovascular Physiology, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goiás, GO, Brazil.
authors.forename: Carlos Henrique
authors.initials: CH
authors.lastname: Xavier
authors.affiliation: Center for Neuroscience and Cardiovascular Physiology, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goiás, GO, Brazil.
authors.forename: André Henrique
authors.initials: AH
authors.lastname: Freiria-Oliveira
authors.affiliation: Center for Neuroscience and Cardiovascular Physiology, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goiás, GO, Brazil.
authors.forename: Diego Basile
authors.initials: DB
authors.lastname: Colugnati
authors.affiliation: Center for Neuroscience and Cardiovascular Physiology, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goiás, GO, Brazil.
authors.forename: Carlos Henrique
authors.initials: CH
authors.lastname: de Castro
authors.affiliation: Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, SP, Brazil.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Colombari
authors.affiliation: Center for Neuroscience and Cardiovascular Physiology, Department of Physiological Sciences, Biological Sciences Institute, Federal University of Goiás, GO, Brazil. Electronic address: pedrino@pq.cnpq.br.
authors.forename: Gustavo Rodrigues
authors.initials: GR
authors.lastname: Pedrino
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D018755:GABA Agonists / Q000008:administration & dosage / Q000494:pharmacology; D007276:Injections, Intraventricular; D007668:Kidney / Q000098:blood supply; D008297:Male; D008845:Microinjections; D009118:Muscimol / Q000008:administration & dosage / Q000494:pharmacology; D011301:Preoptic Area / Q000187:drug effects / Q000502:physiology*; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D012039:Regional Blood Flow; D013045:Species Specificity; D014655:Vascular Resistance
chemical_list: D018755:GABA Agonists; D009118:Muscimol
keywords: Blood pressure; Hypertension; Median preoptic nucleus; SHR