Excitatory amino acid receptors in the dorsomedial hypothalamic area contribute to the chemoreflex tachypneic response.
This study evaluated the effect of blockade of the excitatory amino acid (EAA) receptors in the dorsomedial hypothalamic (DMH) area on the ventilatory and cardiovascular responses of the chemoreflex activation in conscious rats. Bilateral microinjection of kynurenic acid (2.7 nmol, n = 6) into the DMH area reduced the tachypneic (+ 264 ± 13 versus + 204 ± 14 cpm, P < 0.05) and pressor (+ 52 ± 5 versus + 31 ± 6 mmHg, P < 0.05) components of chemoreflex but had no effect on the bradycardic component (-214 ± 7 versus -244 ± 17 bpm) of the chemoreflex. The magnitudes of the reduction in pressor and tachypneic chemoreflex responses were not significantly correlated (r = 0.308, P = 0.330). These data indicate that neurons located in the DMH area are activated by chemoreflex; that this activation is mediated via EAA receptors; and that it is essential for the full expression of the respiratory component of the chemoreflex.
['Silva|Nathália T|NT|', 'Nalivaiko|Eugene|E|', 'da Silva|Luiz G|LG|', 'Haibara|Andréa S|AS|']
D000704:Analysis of Variance D000818:Animals D001794:Blood Pressure D004302:Dorsomedial Hypothalamic Nucleus D004305:Dose-Response Relationship, Drug D004791:Enzyme Inhibitors D018691:Excitatory Amino Acid Antagonists D006339:Heart Rate D007736:Kynurenic Acid D008297:Male D010991:Plethysmography D011190:Potassium Cyanide D051381:Rats D017208:Rats, Wistar D017470:Receptors, Glutamate D012119:Respiration D059246:Tachypnea D013997:Time Factors
Excitatory amino acid receptor Chemoreflex Tachypneic response Dorsomedial hypothalamus