Role of paraventricular nucleus in regulation of sympathetic nerve frequency components.
Autospectral and coherence analyses were used to determine the role of and interactions between paraventricular nucleus (PVN) nitric oxide, gamma-aminobutyric acid (GABA), and the N-methyl-D-aspartic acid (NMDA)-glutamate receptor in regulation of sympathetic nerve discharge (SND) frequency components in anesthetized rats. Four observations were made. First, PVN microinjection of bicuculline (BIC) (GABA(A) receptor antagonist), but not single PVN injections of NMDA (excitatory amino acid) or N(G)-monomethyl-L-arginine (L-NMMA; a nitric oxide synthase inhibitor), altered SND frequency components. Second, combined PVN microinjections of L-NMMA and NMDA changed the SND bursting pattern; however, the observed pattern change was different from that produced by PVN BIC and not observed after sinoaortic denervation. Third, PVN microinjection of kynurenic acid prevented and reversed BIC-induced changes in the SND bursting pattern. Finally, vascular resistance (renal and splenic) was significantly increased after PVN BIC microinjection despite the lack of change in the level of renal and splenic SND. These data demonstrate that the PVN contains the neural substrate for altering SND frequency components and suggest complex interactions between specific PVN neurotransmitters and between PVN neurotransmitters and the arterial baroreceptor reflex in SND regulation.
Kenney
Michael J
MJ
Department of Anatomy and Physiology, Kansas State University, 1600 Denison Avenue, Manhattan, KS 66506, USA. Kenny@vet.ksu.edu
Weiss
Mark L
ML
Mendes
Tammy
T
Wang
Yan
Y
Fels
Richard J
RJ
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D007668:Kidney / Q000098:blood supply; D007736:Kynurenic Acid / Q000494:pharmacology; D008297:Male; D008845:Microinjections; D016202:N-Methylaspartate / Q000494:pharmacology; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D012146:Rest / Q000502:physiology; D013154:Spleen / Q000098:blood supply; D013312:Stress, Physiological / Q000503:physiopathology; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D019323:omega-N-Methylarginine / Q000494:pharmacology
D004791:Enzyme Inhibitors; D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D018756:GABA Antagonists; D019323:omega-N-Methylarginine; D016202:N-Methylaspartate; D007736:Kynurenic Acid; D001640:Bicuculline