Excitatory amino acid receptors mediate asymmetry and lateralization in the descending cardiovascular pathways from the dorsomedial hypothalamus.
The dorsomedial hypothalamus (DMH) and lateral/dorsolateral periaqueductal gray (PAG) are anatomically and functionally connected. Both the DMH and PAG depend on glutamatergic inputs for activation. We recently reported that removal of GABA-ergic tone in the unilateral DMH produces: asymmetry, that is, a right- (R-) sided predominance in cardiac chronotropism, and lateralization, that is, a greater increase in ipsilateral renal sympathetic activity (RSNA). In the current study, we investigated whether excitatory amino acid (EAA) receptors in the DMH-PAG pathway contribute to the functional interhemispheric difference. In urethane (1.2 to 1.4 g/kg, i.p.) anesthetized rats, we observed that: (i) nanoinjections of N-methyl D-aspartate (NMDA 100 pmol/100 nl) into the unilateral DMH produced the same right-sided predominance in the control of cardiac chronotropy, (ii) nanoinjections of NMDA into the ipsilateral DMH or PAG evoked lateralized RSNA responses, and (iii) blockade of EAA receptors in the unilateral DMH attenuated the cardiovascular responses evoked by injection of NMDA into either the R- or left- (L-) PAG. In awake rats, nanoinjection of kynurenic acid (1 nmol/100 nL) into the L-DMH or R- or L-PAG attenuated the tachycardia evoked by air stress. However, the magnitude of stress-evoked tachycardia was smallest when the EAA receptors of the R-DMH were blocked. We conclude that EAA receptors contribute to the right-sided predominance in cardiac chronotropism. This interhemispheric difference that involves EAA receptors was observed in the DMH but not in the PAG.
Laboratório de Fisiologia e Terapêutica Cardiovascular, Departamento Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil; Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Carlos Henrique
CH
Xavier
Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Danielle
D
Ianzer
Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Augusto Martins
AM
Lima
Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Fernanda Ribeiro
FR
Marins
Laboratório de Fisiologia e Terapêutica Cardiovascular, Departamento Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, GO, Brazil.
Gustavo Rodrigues
GR
Pedrino
Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Gisele
G
Vaz
Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Gustavo Batista
GB
Menezes
School of Biomedical Sciences and Pharmacy, University of Newcastle, Newcastle, NSW, Australia.
Eugene
E
Nalivaiko
Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Marco Antônio Peliky
MA
Fontes
D000818:Animals; D004302:Dorsomedial Hypothalamic Nucleus / Q000502:physiology*; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D007839:Functional Laterality / Q000187:drug effects / Q000502:physiology*; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology*; D006652:Histological Techniques; D007736:Kynurenic Acid / Q000008:administration & dosage / Q000494:pharmacology; D016202:N-Methylaspartate / Q000008:administration & dosage / Q000494:pharmacology; D009434:Neural Pathways / Q000378:metabolism; D010487:Periaqueductal Gray / Q000502:physiology*; D051381:Rats; D017470:Receptors, Glutamate / Q000378:metabolism*; D013610:Tachycardia / Q000378:metabolism
D018691:Excitatory Amino Acid Antagonists; D017470:Receptors, Glutamate; D016202:N-Methylaspartate; D007736:Kynurenic Acid