Effects of spinal alpha 1-adrenoceptor antagonism on bladder activity induced by apomorphine in conscious rats with and without bladder outlet obstruction.
To test the hypothesis that the spinal control of micturition involves alpha 1-adrenoceptors, the urodynamic effects of intrathecal and intraarterial alpha 1-adrenoceptor blockade on apomorphine-induced bladder activity in rats were studied. Continuous cystometry was performed in conscious female Sprague-Dawley rats with and without bladder outflow obstruction. In normal rats, subcutaneous apomorphine, 30 micrograms/kg, induced bladder activity that was abolished or attenuated by the alpha 1-adrenoceptor antagonists indoramin and doxazosin given intrathecally or intra-arterially. In rats with outlet obstruction, apomorphine 30 micrograms/kg caused no change in cystometric parameters. However, at a dose of 100 micrograms/kg the drug induced bladder activity, which was attenuated by intrathecal indoramin or doxazosin. These results suggest that the bladder activity evoked by apomorphine-stimulation of bulbospinal pathways can be influenced by alpha 1-adrenoceptors at the spinal and peripheral levels, both in normal rats and in rats with bladder hypertrophy secondary to outlet obstruction.
Ishizuka
O
O
Department of Urology, Lund University Hospital, Sweden.
Mattiasson
A
A
Steers
W D
WD
Andersson
K E
KE
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D018491:Dopamine Agonists / Q000494:pharmacology*; D017292:Doxazosin / Q000494:pharmacology; D005260:Female; D006984:Hypertrophy; D007217:Indoramin / Q000494:pharmacology; D007269:Injections, Intra-Arterial; D007278:Injections, Spinal; D051381:Rats; D017207:Rats, Sprague-Dawley; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D012016:Reference Values; D013116:Spinal Cord / Q000378:metabolism*; D001743:Urinary Bladder / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D001748:Urinary Bladder Neck Obstruction / Q000503:physiopathology*
D000317:Adrenergic alpha-Antagonists; D018491:Dopamine Agonists; D011942:Receptors, Adrenergic, alpha; D007217:Indoramin; D001058:Apomorphine; D017292:Doxazosin