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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.)

Central mechanism of the cardiovascular responses caused by L-proline microinjected into the paraventricular nucleus of the hypothalamus in unanesthetized rats

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Author(s):
Lopes-Azevedo, Silvana ; Busnardo, Cristiane ; Aguiar Correa, Fernando Morgan
Total Authors: 3
Document type: Journal article
Source: Brain Research; v. 1652, p. 43-52, DEC 1 2016.
Web of Science Citations: 0
Abstract

Previously, we reported that microinjection of L-proline (L-Pro) into the paraventricular nucleus of the hypothalamus (PVN) caused vasopressin-mediated pressor responses in unanesthetized rats. In the present study, we report on the central mechanisms involved in the mediation of the cardiovascular effects caused by the microinjection of L-Pro into the PVN. Microinjection of increasing doses of L-Pro (3-100 nmol/100 nL) into the PVN caused dose-related pressor and bradycardic responses. No cardiovascular responses were observed after the microinjection of equimolar doses (33nmol/100nL) of its isomer D-Proline (D-Pro) or Mannitol. The PVN pretreatment with either a selective non-NMDA (NBQX) or selective NMDA (LY235959 or DL-AP7) glutamate receptor antagonists blocked the cardiovascular response to L-Pro (33 nmol/100 nL). The dose-effect curve for the pretreatment with increasing doses of LY235959 was located at the left in relation to the curves for NBQX and DL-AP7, showing that LY235959 is more potent than NBQX, which is more potent than DL-AP7 in inhibiting the cardiovascular response to L-Pro. The cardiovascular response to the microinjection of L-Pro into the PVN was not affected by local pretreatment with N-omega-Propyl-L-arginine (N-Propyl), a selective inhibitor of the neuronal nitric oxide synthase (nNOS), suggesting that NO does not mediate the responses to L-Pro in the PVN. In conclusion, the results suggest that ionotropic receptors in the PVN, blocked by both NMDA and non-NMDA receptor antagonists, mediate the pressor response to L-Pro that results from activation of PVN vasopressinergic magnocellular neurons and vasopressin release into the systemic circulation. (AU)

FAPESP's process: 14/22228-6 - Function of the supraoptic nucleus of the hypothalamus in the cardiovascular and neuroendocrine responses observed in rats submitted to acute restraint stress in rats
Grantee:Silvana Lopes Azevedo
Support Opportunities: Scholarships in Brazil - Post-Doctoral
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 Opportunities: Scholarships in Brazil - Doctorate