CHOLINERGIC, ADRENERGIC AND PURINERGIC RESPONSE OF SEQUENTIAL STRIPS OF RABBIT URINARY-BLADDER

Abstract

The response of 5 sequential segments of rabbit urinary bladder to cholinergic, adrenergic, and purinergic agonists was studied. An abrupt alteration in pharmacological response between bladder body and base occurs at the level of the ureteral orifices. The bladder body responds preferentially to urecholine (muscarinic cholinergic), isoproterenol (.beta.-adrenergic) and ATP (purinergic), whereas the bladder base responds preferentially to methoxamine (.alpha.-adrenergic). The density of both muscarinic cholinergic receptors ([3H]quinuclidinyl benzilate binding sites) and .beta.-adrenergic receptors was significantly higher in the body than in the base, whereas the concentration of .alpha.-adrenergic receptors was greater in the bladder base than in the body. The differences in the response of the bladder base and body to cholinergic and adrenergic agents are apparently primarily due to differences in the densities of the specific autonomic receptors. The response of the bladder to ATP (which is a putative neurotransmitter in the urinary bladder) can also be separated between body and base. The distribution is similar to that observed for urecholine.