A potential role of central A sub(1) adenosine receptors in the responses to hypothalamic stimulation in the anaesthetized cat

In pentobarbitone anaesthetized and paralysed cats the effects of the A sub(1) adenosine antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX) have been observed on the pressor response to stimulation of the hypothalamic defense area (HDA) and on the effects of baroreceptor and chemoreceptor reflex activation on arterial blood pressure. The administration of DPCPX decreased the magnitude of the HDA pressor response and the chemoreceptor induced rise in blood pressure. The fall in blood pressure induced by baroreceptor activation was enhanced to a small yet significant extent. No changes were observed in the tachypnoea evoked by hypothalamic defence area (HDA) stimulation. These results suggest a possible role for central adenosine A sub(1) receptors in mediating the cardiovascular changes evoked during HDA stimulation.