Age related changes in the functional, biochemical and molecular properties of alpha1-adrenoceptors in the rat genitourinary tract.
OBJECTIVE
Because age related changes occur in the properties of alpha(1)-adrenoceptor in several mammalian tissues and alpha(1)-adrenoceptor antagonists are extensively used to treat lower urinary tract symptoms secondary to benign prostatic hyperplasia, we investigated age related changes in the functional, biochemical and molecular properties of alpha(1)-adrenoceptor in the rat genitourinary tract.


METHODS
The characteristics of alpha(1)-adrenoceptor in the ventral and dorsolateral prostate, and bladder base and dome of 3 and 22-month-old rats were determined using an isolated muscle bath, radioligand receptor binding and real-time reverse transcriptase-polymerase chain reaction techniques.


RESULTS
Old rats had significantly higher body weight, lower testosterone, a smaller ventral prostate and a larger bladder dome than young rats. Although there was no significant age dependent difference in the properties of alpha(1)-adrenoceptor in the bladder base and dome, total alpha(1)-adrenoceptor density, mRNA expression of all 3 alpha(1)-adrenoceptor subtypes (alpha(1A), alpha(1B) and alpha(1D)) and the maximum contractile responses to phenylephrine were significantly lower in the ventral and dorsolateral prostate of 22 vs 3-month-old rats.


CONCLUSIONS
Age related differences in the molecular, biochemical and functional properties of alpha(1)-adrenoceptors in the rat genitourinary tract may indicate potential differences in the response to alpha(1)-adrenoceptor antagonists with aging, ie a decrease in the therapeutic response in old vs young rats in the response to alpha(1)-adrenoceptor antagonists when used to treat lower urinary tract symptoms secondary to benign prostatic hyperplasia.
Yono
Makoto
M
Section of Urology, Yale University School of Medicine, New Haven, CT 06520, USA.
Foster
Harris E
HE
Weiss
Robert M
RM
Latifpour
Jamshid
J
D000367:Age Factors; D000818:Animals; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000502:physiology; D011467:Prostate / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*; D001743:Urinary Bladder / Q000502:physiology*
D018340:Receptors, Adrenergic, alpha-1