Back to Search Start Over

Cardiovascular effects of L-glutamate microinjection in the supraoptic nucleus of unanaesthetized rats.

Authors :
Busnardo C
Tavares RF
Antunes-Rodrigues J
CorrĂȘa FM
Source :
Neuropharmacology [Neuropharmacology] 2007 May; Vol. 52 (6), pp. 1378-84. Date of Electronic Publication: 2007 Feb 04.
Publication Year :
2007

Abstract

We report on the cardiovascular effects of L-glutamate (L-glu) microinjection in the hypothalamic supraoptic nucleus (SON) as well as possible receptor and mechanisms involved. Microinjection of L-glu in 100 nL in the SON caused dose-related pressor and bradycardic responses in unanesthetized rats. Responses were markedly reduced in urethane-anesthetized rats. The response to L-glu 10 nmol was blocked by local pretreatment with 2 nmol of the non-NMDA-receptors antagonist NBQX and not affected by 2 nmol of the selective NMDA-receptor antagonist LY 235959, suggesting that non-NMDA receptors mediate these responses. The pressor and bradycardic response to L-glu was potentiated by intravenous pretreatment with the ganglion blocker pentolinium and was blocked by intravenous pretreatment with the V1-vasopressin receptor antagonist dTyr(CH2)5(Me)AVP, suggesting involvement of circulating vasopressin in this response. Additionally L-glu microinjection into the SON increased plasma vasopressin levels (control: 1.3 +/- 0.2 pg/mL, n = 6; L-glu: 14.7+/-2.3 pg/mL, n=6). In conclusion the results suggest that pressor responses to SON microinjection of L-glu are caused by activation of non-NMDA glutamate receptors and mediated by vasopressin release into systemic circulation.

Details

Language :
English
ISSN :
0028-3908
Volume :
52
Issue :
6
Database :
MEDLINE
Journal :
Neuropharmacology
Publication Type :
Academic Journal
Accession number :
17367824
Full Text :
https://doi.org/10.1016/j.neuropharm.2007.01.011