ESTROGEN-INDUCED ALTERATIONS IN THE AUTONOMIC RESPONSES OF THE RABBIT URINARY-BLADDER

  • 1 January 1980
    • journal article
    • research article
    • Vol. 215  (3) , 614-618
Abstract
The effect of estrogen administration on the autonomic innervation of the rabbit urinary bladder was studied. Immature female white rabbits were injected twice daily with estrogen (150 .mu.g/kg) for 4 consecutive days. Control animals received injections of vehicle. The response of bladder strips to the following agonists were determined for control and estrogen-treated animals: methoxamine (.alpha. adrenergic); isoproterenol (.beta. adrenergic); bethanechol (muscarinic cholinergic); ATP (purinergic) and KCl (nonreceptor mediated). Additionally, the adrenergic and cholinergic receptor densities were determined by standard radioligand binding techniques. Estrogen induced a marked increase in the response to .alpha. adrenergic, muscarinic cholinergic and purinergic agonists in the bladder body and midbladder. No significant alterations were noted in the bladder base. No alterations were noted for isoproterenol or KCl. The receptor densities paralleled closely the physiological responses. Estrogen induced a significant increase in .alpha. adrenergic and muscarinic receptors in the bladder body and midsection, but no change was noted in the receptor density of the bladder base. Estrogen did not alter the .beta. receptor density. These findings indicate that the urinary bladder responds as a target organ for estrogen-induced alterations in autonomic innervation.