Excitatory Amino Acid Receptors Mediate Asymmetry and Lateralization in the Descending Cardiovascular Pathways from the Dorsomedial HypothalamusReport as inadecuate




Excitatory Amino Acid Receptors Mediate Asymmetry and Lateralization in the Descending Cardiovascular Pathways from the Dorsomedial Hypothalamus - Download this document for free, or read online. Document in PDF available to download.

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.



Author: Carlos Henrique Xavier , Danielle Ianzer, Augusto Martins Lima, Fernanda Ribeiro Marins, Gustavo Rodrigues Pedrino, Gisele Vaz, G

Source: http://plos.srce.hr/



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