Coupled Nitric Oxide and Autonomic Receptor Functional Responses in the Normal and Inflamed Urinary Bladder of the Rat
Abstract
Both divisions of the autonomic nervous system are involved in regulation of urinary bladder function. Several substances, other than noradrenaline and acetylcholine, seem to play important roles in physiology and pathophysiology of lower urinary tract.
In the current study, we aimed to examine if there exist interplays between nitric oxide (NO) and autonomic transmitters and if such interactions vary in different parts of the urinary bladder in healthy and cyclophosphamide (CYP)-induced cystitic rats; when administered to the animals (100 mg/kg; i.p.), the cytotoxic CYP metabolite acrolein induces bladder inflammation. In the current study a series of in vitro functional studies were performed on detrusor muscle strip preparations.
Stimulation with electrical field stimulation (EFS), methacholine, adenosine 5'-triphosphate (ATP), and adrenaline evoked contractile responses in isolated bladder preparations that were significantly reduced in cyclophosphamide (CYP)-treated rats. The study shows that both contractile and relaxatory functions are altered in the state of inflammation.
The parasympathetic nerve-mediated contractions of the body of the bladder, evoked by the release of ATP and acetylcholine, were substantially reduced in cystitis. The relaxations to p-adrenoceptor and purinoceptor stimulation were also reduced but only the ATP-evoked relaxation involved NO.