title: Hypothalamic disconnection caudal to paraventricular nucleus affects cardiovascular and drinking responses to central angiotensin II and carbachol.
abstract: The paraventricular nucleus of the hypothalamus (PVN) is an important area of the brain involved in the control of cardiovascular system and fluid-electrolyte balance. In the present study we evaluated the effects of hypothalamic disconnection (HD) caudal to PVN in the pressor and dipsogenic responses induced by intracerebroventricular (icv) injections of angiotensin II (ANG II) or carbachol (cholinergic agonist). Male Holtzman rats (280-320 g) with a stainless steel cannula implanted into the lateral ventricle and submitted to sham or HD surgery were used. HD (2 or 15 days) reduced the pressor responses to ANG II (50 ng/1μl) icv (8±3 and 11±3 mm Hg, respectively, vs. sham: 23±3 and 21±2 mm Hg) or carbachol (4 nmol/1 μl) icv (8±2 and 21±3 mm Hg, respectively, vs. sham: 33±3 and 33±3 mm Hg), without changing baseline arterial pressure. Acutely (2-4 days), HD also reduced water intake to icv ANG II (3.3±2.2 vs. sham: 14.2±3.0 ml/60 min) or carbachol (4.4±1.8 vs. sham: 11.4±1.6 ml/60 min); however, chronically (15-17 days), HD produced no change on ANG II- and carbachol-induced water intake, in spite of the increased daily water intake and urinary volume. The results suggest that medial projections caudal to PVN are important for pressor and dipsogenic responses to central angiotensinergic and cholinergic activation.
authors.affiliation: Department of Physiology and Pathology, School of Dentistry, UNESP—São Paulo State University Araraquara, SP, Brazil.
authors.forename: Lilia Simone
authors.initials: LS
authors.lastname: Urzedo-Rodrigues
authors.forename: Tatiane
authors.initials: T
authors.lastname: Depieri
authors.forename: Anderson Julio
authors.initials: AJ
authors.lastname: Cherobino
authors.forename: Oswaldo U
authors.initials: OU
authors.lastname: Lopes
authors.forename: José V
authors.initials: JV
authors.lastname: Menani
authors.forename: Débora S A
authors.initials: DS
authors.lastname: Colombari
mesh_terms: D000804:Angiotensin II / Q000008:administration & dosage*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002217:Carbachol / Q000008:administration & dosage*; D002320:Cardiovascular Physiological Phenomena; D002319:Cardiovascular System / Q000187:drug effects*; D018679:Cholinergic Agonists / Q000008:administration & dosage*; D004326:Drinking / Q000502:physiology*; D007276:Injections, Intraventricular; D008297:Male; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014882:Water-Electrolyte Balance / Q000187:drug effects / Q000502:physiology
chemical_list: D018679:Cholinergic Agonists; D000804:Angiotensin II; D002217:Carbachol