CLONING AND EXPRESSION OF A BOVINE ADENOSINE-A1-RECEPTOR CDNA

A bovine brain adenosine A1 receptor cDNA encoding a 326 amino acid protein has been identified. This cDNA, which encodes a protein > 90% identical to analogous rat and dog receptors, was transiently expressed in COS-1 cells. Recombinant receptors exhibited the features of bovine A1 receptors that distinguish it from rat and canine receptors, including subnanomolar K(i) for 1,3-dipropyl-8-cyclopentylxanthine, R-phenylisopropyl-adenosine (R-PIA) and xanthine amino conjugate, and the distinct potency order: R-PIA > S-PIA >> 5'-N-ethylcarboxamidoadenosine > 2'-chloroadenosine. The results indicate that the pharmacological differences between A1 adenosine receptors among species result from only minor differences in receptor structures.