BETA-ADRENERGIC-RECEPTOR SUBTYPES IN HUMAN PINEAL-GLAND

The secretion of melatonin by the pineal has been promoted as a direct monitor of adrenergic function in depressive illness. However, discre pant findings have been reported, possibly reflecting a complex adrene rgic regulation of pineal output. In order to clarify the anatomical l ocalization and relative density of beta-adrenegic receptors and their subtypes in human pineal, quantitative autoradiographic analysis was conducted of beta-adrenergic receptors in postmortem specimens using t he high affinity radioligand I-125 pindolol. Dense specific binding wa s found throughout the gland. beta(1)-adrenergic receptors were more n umerous, but beta(2)-receptors were present in an overlapping anatomic al distribution with beta(1)-receptors.