Mz. Goren et al., Cardiovascular responses to NMDA injected into nuclei of hypothalamus or amygdala in conscious rats, PHARMACOL, 61(4), 2000, pp. 257-262
The nuclei of hypothalamus and amygdala have been shown to be involved in t
he central cardiovascular homeostasis. Recent studies suggest that glutamat
e-containing neurons have an important role in the regulation of the centra
l cardiovascular function. In this study, we demonstrate the roles of the c
entral nucleus of the amygdala and the paraventricular nucleus of the amygd
ala and the paraventricular nucleus or the dorsomedial nucleus of the hypot
halamus in N-methyl-D-aspartate (NMDA) induced blood pressure and heart rat
e changes in conscious Sprague-Dawley rats. Intracerebroventricular or pare
nchymal injections of NMDA evoke increases in arterial pressure. The NMDA-i
nduced elevations in brood pressure are more prominent when NMDA is adminis
tered into the dorsomedial nucleus of the hypothalamus, Microinjections of
NMDA into the dorsomedial hypothalamus exert significant heart rate increas
es, whereas NMDA when administered into the paraventricular nucleus of the
hypothalamus or into the central nucleus of the amygdala has no significant
effect on the heart rate. The dorsomedial nucleus of the hypothalamus is f
ound to be the most effective site in this respect, The present study provi
des strong evidence for the tonic glutamatergic influence on blood pressure
and heart rate via NMDA receptors located within the dorsomedial nucleus a
nd to a lesser extent via those located within the paraventricular nucleus
of the hypothalamus. Copyright(C) 2000 S. Karger AG, Basel.