α₁-Adrenergic Receptors in the Mammalian Cochlea

Abstract

Liu SY, Pitovski DZ, Shivapuja BG. α-adrenergic receptors in the mammalian cochlea. Acta Otolaryngol (Stockh) 1996; 116: 710-713.

The presence of α₁, -adrenergic receptors in the mammalian cochlea has previously been suggested by physiological experiments using antagonists specific to the receptor. However, the characterises of adrenergic receptors in the cochlea have not been described. by employing [H]-prazosin, high affinity, specific binding sites with characteristics of α₁, -adrenergic receptors have now been identified and characterized in the chinchilla cochlea. Analysis of the specific [H]-prazosin binding indicates that prazosin binds to a single class of high-affinity sites with a dissociation constant, k_d, of 2.9 10⁻⁹ M and a maximum number of binding sites, B_max, of 30 fmol/mg dry tissue. Furthermore, the binding characteristics suggest that these receptors may be related to the microvasculature of the cochlea. These results provide a rational basis for the observed actions of a-adrenergic drugs on the auditory system.

Key Words:

• α₁-adrenergic receptors
• cochlea k_d B_mar prazosin
• [H]-prazosin