PO2-dependent changes in intrinsic and extrinsic tongue muscle activities in the rat.

Rationale: Historically, respiratory-related research in sleep apnea has focused exclusively on the extrinsic tongue muscles (i.e., genioglossus, hyoglossus, and styloglossus).

Dopaminergic excitation of the goat carotid body is mediated by the serotonin type 3 receptor subtype.

The purpose of the present study was to use chemoafferent recordings from the goat carotid body (CB) to pharmacologically identify the putative low affinity excitatory receptor for dopamine (DA). Close arterial injections of DA (1-50 microg kg(-1)) induced a dose-dependent excitatory burst followed by inhibition of the CB chemoafferent activity. The inhibition is likely DA D(2) receptor-mediated as it was blocked by domperidone (0.