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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Mechanism of the cardiovascular responses caused by L-proline microinjected into the supraoptic nucleus of the hypothalamus in unanesthetized rats

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Author(s):
Lopes-Azevedo, Silvana [1] ; Busnardo, Cristiane [1] ; Aguiar Correa, Fernando Morgan [1]
Total Authors: 3
Affiliation:
[1] Univ Sao Paulo, Dept Pharmacol, Sch Med Ribeirao Preto, BR-14049900 Ribeirao Preto, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: Amino Acids; v. 45, n. 4, p. 797-810, OCT 2013.
Web of Science Citations: 2
Abstract

In the present study, we report on the cardiovascular effects caused by the microinjection of l-proline (l-Pro) into the supraoptic nucleus (SON) in unanesthetized rats: the possible involvement of ionotropic glutamate receptors in the SON, as well as the peripheral mechanisms involved in the mediation of its cardiovascular effects. We compared the l-Pro effects with those caused by the injection of l-glutamate (l-Glu) into the SON. Microinjection of increasing doses of l-Pro into the SON caused dose-related cardiovascular responses in unanesthetized rats that were similar to those observed after the injection of l-Glu. Pretreatment of the SON with either a selective non-NMDA (NBQX) or a selective NMDA (LY235959) glutamate receptor antagonist blocked the cardiovascular response to l-Pro. The dose-effect curve for the pretreatment with increasing doses of LY235959 was shifted to the left in relation to the curve for NBQX, showing that LY235959 is more potent than NBQX in inhibiting the cardiovascular response to l-Pro. On the other hand, the cardiovascular response to l-Glu was only significantly reduced by pretreatment with NBQX (2 nmol/100 nL), but not affected by LY235959 (2 nmol/100 nL). The pressor response to l-Pro was not affected by intravenous pretreatment with the ganglion blocker pentolinium, but it was blocked by intravenous pretreatment with the V-1-vasopressin receptor antagonist dTyr(CH2)(5)(Me)AVP. In conclusion, these results suggest that l-Pro has a selective receptor that is sensitive to ionotropic glutamate receptor antagonists. Its activation in the SON results in vasopressin release into the systemic circulation, causing pressor and bradycardiac responses. (AU)

FAPESP's process: 10/11303-6 - Study of the cardiovascular effects caused by the microinjection of L-proline into hypothalamic nuclei of unanesthetized rats
Grantee:Silvana Lopes Azevedo
Support type: Scholarships in Brazil - Doctorate