A role for K ATP+-channels in mediating the elevations of cerebral blood flow and arterial pressure by hypoxic stimulation of oxygen-sensitive neurons of rostral ventrolateral medulla

Reticulospinal sympathoexcitatory neurons of rostral ventrolateral medulla (RVL) are selectively excited by hypoxia to elevate arterial pressure (AP) and cerebral blood flow (rCBF), that are elements of the oxygen-conserving (diving) reflex. We investigated whether K ATP +-channels participate in this. Tolbutamide and glibenclamide, K ATP +-channel blockers, microinjected into RVL in anesthetized rats, dose-dependently and site-specifically elevated AP and rCBF and potentiated responses to hypoxemia. K ATP +-channels may mediate hypoxic excitation of oxygen-sensing RVL neurons.