Abstract
As early as 1906 Dale (1) reported that adrenaline causes relaxation of detrusor muscle and contraction of the vesical sphincter. However, the response of ureter to sympathomimetic amines is indefinite; some experiments indicate that the motility and tone of the ureter are lessened (2) while in the rabbit Ahlquist (3) observed a stimulant effect of the amines on the ureter. A similar effect was observed on the isolated ureters of buffalo (4), dog and pig (5-8). Ergotamine has been shown to block the stimulant effect of adrenaline on the vesical sphincter (1) but it does not block the inhibitory effect on the detrusor muscle (1). The ergotamine block indicates that the effect of adrenaline on the vesical sphincter was mediated through the alpha adrenergic receptors and the effect on the detrusor muscle could be through the beta receptors (3). Furthermore, on the basis of relative potencies of different sympathomimetic amines, Ahlquist (3) proposed alpha adrenergic receptors for the stimulant action on the ureter. The use of beta receptor blocking agent, dichloroisopropyl noradrenaline (DCI) has helped in demonstrating the presence of beta receptors in various tissues (9). The existence of beta receptors in the urinary bladder of cat has been recently demonstrated (10). The present work was undertaken to analyse the adrenergic receptors in the ureter, detrusor muscle and vesical sphincter of dog with the help of alpha as well as beta receptor blocking agents.
