Insular cortex alpha(1)-adrenoceptors modulate the parasympathetic component of the baroreflex in unanesthetized rats

Autor(es)

Alves, Fernando H. F. ^[1] ; Crestani, Carlos C. ^[1] ; Resstel, Leonardo B. M. ^[1] ; Correa, Fernando M. A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sch Med Ribeirao Preto, Dept Pharmacol, BR-14049900 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Brain Research; v. 1295, p. 119-126, OCT 12 2009.
• Citações Web of Science: 14

Resumo

The insular cortex (IC) has been reported to modulate the cardiac parasympathetic activity of the baroreflex in unanesthetized rats. However, which neurotransmitters are involved in this modulation is still unclear. In the present study, we evaluated the possible involvement of local IC-noradrenergic neurotransmission in modulating reflex bradycardiac responses. Bilateral microinjection of the selective alpha(1)-adrenoceptor antagonist WB4101 (15 nmol/100 nL), into the IC of male Wistar rats, increased the gain of reflex bradycardia in response to mean arterial pressure (MAP) increases evoked by intravenous infusion of phenylephrine. However, bilateral microinjection of equimolar doses of either the selective alpha(2)-adrenoceptor antagonist RX821002 or the non-selective beta-adrenoceptor antagonist propranolol into the IC did not affect the baroreflex response. No effects were observed in basal MAP or heart rate values after bilateral microinjection of noradrenergic antagonists into the IC, thus suggesting no tonic influence of IC-noradrenergic neurotransmission on resting cardiovascular parameters. In conclusion, these data provide evidence that local IC-noradrenergic neurotransmission has an inhibitory influence on baroreflex responses to blood pressure increase evoked by phenylephrine infusion through activation of alpha(1)-adrenoceptors. (C) 2009 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 06/57670-4 - Estudo da participação da neurotransmissão noradrenérgica do núcleo leito da estria terminal na regulação do sistema cardiovascular em ratos
• Beneficiário: Carlos Cesar Crestani
• Modalidade de apoio: Bolsas no Brasil - Doutorado