Intrathecal injection of Brilliant Blue G, a P2X7 antagonist, attenuates the exercise pressor reflex in rats.

Intrathecal injection of Brilliant Blue G, a P2X7 antagonist, attenuates the exercise pressor reflex in rats. Am J Physiol Regul Integr Comp Physiol. 2020 Jul 01;: Authors: Estrada JA, Ducrocq GP, Kim JS, Kaufman MP Abstract Purinergic 2X receptors (P2X) on the endings of group III and IV afferents play a role in evoking the exercise pressor reflex. Particular attention has been paid to P2X3 receptors because their blockade in the periphery attenuated this reflex. In contrast, nothing is known about the role played by P2X receptors in the spinal cord in evoking the exercise pressor reflex in rats. P2X7 receptors, in particular, may be especially important in this regard because they are found in abundance on spinal glial cells and may communicate with neurons to effect reflexes controlling cardiovascular function. Consequently, we investigated the role played by spinal P2X7 receptors in evoking the exercise pressor reflex in decerebrated rats. We found that intrathecal injection of the P2X7 antagonist Brilliant Blue G (BBG) attenuated the exercise pressor reflex (Blood Pressure Index: 294 ± 112 mmHg·s pre vs 7 ± 32 mmHg·s post; P < 0.05). Likewise, intrathecal injection of minocycline, which inhibits microglial cell output, attenuated the reflex. In contrast, intrathecal injection of BBG did not attenuate the pressor response evoked by intra-carotid injection of sodium cyanide, a maneuver that stimulated carotid chemoreceptors...
Source: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology - Category: Physiology Authors: Tags: Am J Physiol Regul Integr Comp Physiol Source Type: research