Molecular and pharmacological characterization of the canine brainstem alpha-2A adrenergic receptor

This study characterizes the alpha(2)-adrenergic receptors present in canin e brainstem. Radioligand binding and reverse transcriptase-polymerase chain reaction (RT-PCR) experiments were performed in canine brainstem to identi fy the receptors present and determine the pharmacological properties of th ese receptors. The pK(i) values derived from radioligand competition curves for a number of adrenergic receptor agents at the four alpha(2)-adrenergic receptor subtypes were compared to the canine brainstem. The pK(i) values at the canine brainstem alpha(2)-adrenergic receptor were consistent with t he presence of the alpha(2A)-Aadrenergic receptor. To determine whether the canine brainstem expressed the message for the alpha(2A)-adrenergic recept or, RT-PCR was performed with specific primers for the four subtypes of alp ha(2)-adrenergic receptors, In the canine brainstem, only the primers corre sponding to a region in the human alpha(2A)-adenergic receptor produced a P CR product, No bands were detected in the canine brainstem lanes with the a lpha(2B)-, alpha(2C)-, or alpha(2D)-receptor primers. These data suggest th at the canine brainstem contains the alpha(2A)-adrenergic receptor.