[Alpha1-adrenoceptor subtypes in rabbit penile corpus cavernosum].
OBJECTIVE
To study alpha(1)- adrenoceptor (alpha(1)- AR) subtypes with the functional role and the distribution of its subtypes in rabbit penile corpus cavernosum.


METHODS
The rabbit penile corpus cavernosum was studied by using functional experiment and radioligand binding assay.


RESULTS
In the radioligand binding assay, the maximal binding capacity (Bmax of (125)IBE and alpha(1)-AR) decreased obviously after pretreatment with chloroethylclonidine (CEC), which were 746 +/- 236 fmol/mg protein and 214 +/- 71 fmol/mg protein, respectively. Alpha(1A)-, alpha(1D)-and alpha(1B)-AR took about 20%, 25% and 55%, respectively. In the functional experiments, the maximal contraction induced by norepinephrine (NE) was not decreased significantly after pretreatment with CEC. The pA(2) values of two alpha(1)-AR selective antagonists, 5-MU, BMY7378, for antagonizing NE-induced penile corpus cavernosum contraction had a high correlative association with the pK(I) values for cloned alpha(1A)-AR.


CONCLUSIONS
The functional alpha(1)-AR subtype is alpha(1A)-AR although there are three subtypes in the penile corpus cavernosum.
Peng
M
M
Institute of Urology, Beiing Medical University, Beijing 100034.
Zhang
Y
Y
Xue
Z
Z
Han
Q
Q
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D003000:Clonidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D010410:Penile Erection / Q000187:drug effects; D010413:Penis / Q000378:metabolism*; D010879:Piperazines / Q000494:pharmacology; D020033:Protein Isoforms / Q000378:metabolism; D011817:Rabbits; D011869:Radioligand Assay; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism*
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D010879:Piperazines; D020033:Protein Isoforms; D018340:Receptors, Adrenergic, alpha-1; C057446:5-methylurapidil; C051731:chlorethylclonidine; C053428:BMY 7378; D003000:Clonidine; D009638:Norepinephrine