title: The hypothalamic paraventricular nucleus and carotid receptors modulate hyperglycemia induced by hemorrhage.
abstract: The aim of this study was to assess the role of cholinergic transmission in the paraventricular nucleus of the hypothalamus (PVN) and carotid body receptors in mediating a rise in plasma glucose levels in response to hemorrhagic hypotension in rats. Methylatropine (1x10(-9) mol) or 0.15 M NaCl (0.2 microl) was injected into the PVN of Wistar rats weighing 250-300 g bearing a chronic jugular catheter for blood sampling and hemorrhage (1.2 ml/100 g/2 min). Polyethylene cannulae (PE-10) were inserted into the left femoral artery for cardiovascular monitoring. In the other experimental protocol, hemorrhage was performed on rats submitted to bilateral carotid receptor denervation (H-CD). The results show that the hyperglycemic response to hemorrhage was decreased by either methylatropine (H-MA) treatment or bilateral carotid receptor denervation (10.3+/-0.4 mM, control, n=15 vs. 7.7+/-0.2 mM, H-MA, n=12, and 7.6+/-0.3 mM, H-CD, n=5, p<0.01). Furthermore, methylatropine did not affect the recovery of blood pressure after hemorrhage-induced hypotension, suggesting that the metabolic and pressor adjustments have different efferent pathways. Our data demonstrate that cholinergic input from the PVN and carotid receptors (chemo- and/or baroreceptors) might participate in the same neural pathway activated by hemorrhage-induced hypotension that produces hyperglycemia.
authors.affiliation: Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, ICB-UFMG, 6627 Av. Antonio Carlos, 31270-901 Belo Horizonte, MG, Brazil.
authors.forename: Simonton Andrade
authors.initials: SA
authors.lastname: Silveira
authors.forename: Nilo Resende
authors.initials: NR
authors.lastname: Viana Lima
authors.forename: Andréa Siqueira
authors.initials: AS
authors.lastname: Haibara
authors.forename: Cândido Celso
authors.initials: CC
authors.lastname: Coimbra
mesh_terms: D000818:Animals; D001286:Atropine Derivatives; D001786:Blood Glucose / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002339:Carotid Arteries; D002344:Carotid Body / Q000503:physiopathology*; D003714:Denervation / Q000379:methods; D006339:Heart Rate / Q000187:drug effects; D006470:Hemorrhage / Q000139:chemically induced / Q000150:complications*; D006943:Hyperglycemia / Q000139:chemically induced / Q000209:etiology*; D008297:Male; D008845:Microinjections / Q000379:methods; D008954:Models, Biological; D010286:Paraventricular Hypothalamic Nucleus / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride / Q000494:pharmacology; D013223:Statistics as Topic; D013997:Time Factors
chemical_list: D001286:Atropine Derivatives; D001786:Blood Glucose; D012965:Sodium Chloride; C006649:methylatropine