Age-related changes in Ca2+ channel antagonist receptors in rabbit lower urinary tract.
(+)-[3H]PN 200-110 and [3H]nitrendipine binding sites were studied in 1 day, 6 week, 6 month and 4.5-5 year rabbit urethra, bladder base and bladder dome. In all age groups, the density of these Ca2+ channel antagonist binding sites was significantly greater in the urethra than in the bladder base or bladder dome, except that the density of [3H]nitrendipine binding sites in the 1 day rabbit was similar in all three regions. In the urethra the maximum number of binding sites for (+)-[3H]PN 200-110 was twice that for [3H]nitrendipine. In the bladder base and bladder dome both Ca2+ channel antagonists labelled a similar number of binding sites. For both ligands, the Bmax values for the Ca2+ channel antagonists in the urethra increased from 1 day to 6 weeks and then decreased. In the bladder base and dome, however, the receptor density decreased gradually or was unchanged with aging. The pharmacological profiles of these binding sites in 1 day and 6 month urethra and bladder dome showed K1 values with the following rank order: nitrendipine < niguldipine < BAY K 8644. These data demonstrate the presence of regional- and age-dependent changes in the density of Ca2+ channel antagonist binding sites in the lower urinary tract of the rabbit.
Yoshida
M
M
Section of Urology, Yale University School of Medicine, New Haven, CT 06510.
Latifpour
J
J
Weiss
R M
RM
D000375:Aging / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight / Q000187:drug effects; D002120:Calcium Channel Agonists / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism*; D005260:Female; D066298:In Vitro Techniques; D017275:Isradipine / Q000378:metabolism / Q000493:pharmacokinetics; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism; D009568:Nitrendipine / Q000378:metabolism / Q000493:pharmacokinetics; D009929:Organ Size / Q000187:drug effects; D011817:Rabbits; D014521:Urethra / Q000378:metabolism; D001743:Urinary Bladder / Q000378:metabolism; D014551:Urinary Tract / Q000378:metabolism*
D002120:Calcium Channel Agonists; D015220:Calcium Channels; D009568:Nitrendipine; D017275:Isradipine