title: Glutamatergic neurotransmission in the hypothalamus PVN on heart rate variability in exercise trained rats.
abstract: The paraventricular nucleus of hypothalamus (PVN) is a well known site of integration for autonomic and cardiovascular responses, and the glutamate neurotransmitter plays an important role. The aim of our study was to evaluate the cardiovascular parameters and autonomic modulation by means of spectral analysis after ionotropic glutamate receptor inhibition in the PVN in conscious sedentary (S) or swimming trained (ST) rats. After exercise training protocol, adult male Wistar rats, instrumented with guide cannulae to PVN and artery and vein catheters were submitted to mean arterial pressure (MAP) and heart rate (HR) recording. At baseline, physical training induced a resting bradycardia (S: 379 ± 3, ST: 349 ± 2 bpm, Pb<0.05) and promoted adaptations in HRV characterized by an increase of HF in normalized values and a decrease of LF in absolute and normalized units compared with the sedentary group. Microinjection of kynurenic acid (KYNA) in the PVN of sedentary and trained rats promoted decreases in MAP and HR, but the decrease in HR was smaller in the trained animals (ΔHRS: -48 ± 7, ST: -28 ± 4 bpm, Pb<0.05). Furthermore, the differences in baseline parameters of pulse interval, found between sedentary and trained animals, disappeared after KYNA microinjection in the PVN. Our data suggest that the cardiovascular and autonomic adaptations to the heart induced by exercise training may involve glutamatergic mechanisms in the PVN.
authors.affiliation: Department of Physiological Sciences, Center of Biological Sciences, State University of Londrina, PR, Brazil.
authors.forename: Rosiane Batista
authors.initials: RB
authors.lastname: Mastelari
authors.forename: Samantha
authors.initials: S
authors.lastname: Bagolan de Abreu
authors.forename: Fernando
authors.initials: F
authors.lastname: Morgan de Aguiar Corrêa
authors.forename: Hugo Celso
authors.initials: HC
authors.lastname: Dutra de Souza
authors.forename: Marli Cardoso
authors.initials: MC
authors.lastname: Martins-Pinge
mesh_terms: D000818:Animals; D062186:Arterial Pressure / Q000187:drug effects / Q000502:physiology; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D018698:Glutamic Acid / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D007736:Kynurenic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008845:Microinjections; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*
chemical_list: D018691:Excitatory Amino Acid Antagonists; D018698:Glutamic Acid; D007736:Kynurenic Acid