Dorsal periaqueductal gray area synapses modulate baroreflex in unanesthetized rats.
Auton Neurosci
; 131(1-2): 70-6, 2007 Jan 30.
Article
em En
| MEDLINE
| ID: mdl-16914391
ABSTRACT
The dorsal portion of the periaqueductal gray area (dPAG) is involved in behavioral and cardiovascular control. We report the effect of acute and reversible dPAG blockade by local microinjection of either lidocaine or CoCl2 on the baroreflex response of unanesthetized rats. Acute and reversible blockade evoked by lidocaine microinjection into the dPAG did not affect the bradycardic response to mean arterial pressure (MAP) increases evoked by i.v. infusion of phenylephrine. However, lidocaine increased baroreflex gain and tachycardic reflex in response to MAP decreases evoked by i.v. infusion of sodium nitroprusside, thus suggesting an action on the sympathetic component of the baroreflex. The effects of dPAG synapses blockade caused by CoCl2 were similar to those observed after lidocaine microinjection. CoCl2 microinjection also increased baroreflex gain and tachycardiac responses to MAP decreases without affecting the parasympathetic baroreflex component. In conclusion, our data point to a dPAG tonic inhibitory involvement in baroreflex control, specifically modulating the sympathetic baroreflex component. Temporary dPAG ablation by local microinjection of lidocaine increased the sympathetic baroreflex component. Because CoCl2 microinjection had similar effects on the baroreflex, this modulation involves local synaptic neurotransmission within the dPAG.
Buscar no Google
Bases de dados:
MEDLINE
Assunto principal:
Sinapses
/
Substância Cinzenta Periaquedutal
/
Barorreflexo
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Revista:
Auton Neurosci
Assunto da revista:
NEUROLOGIA
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Brasil