Effects of Several Autonomic Drugs on the Responses of the Isolated Rabbit Detrusor Muscle Strips to Electrical Stimulation / 대한비뇨기과학회지

Effects of several autonomic drugs on the responses of the isolated rabbit detrusor muscle strips to electrical stimulation were investigated. Electric stimulation of the detrusor muscle strips elicited two different responses; (a) contraction followed by relaxation in 14 cases out of 22 experiments, and (b) contraction only in 8 cases. The contraction responses to electrical stimulation were significantly reduced in the presence of either atropine or regitine, respectively The relaxation response to electrical stimulation was abolished in the presence of propranolol. Addition of norepinephrine evoked one of following three responses: (a) relaxation in 10 cases out of 19 experiments, (b) contraction in 6 cases, and (c) contraction followed by relaxation in 4 cases. The relaxation response to norepinephrine was reversed. in the presence of propranolol, to a contraction response which was then abolished after administration of regitine. The contraction response to norepinephrine was reversed, in the presence of regitine, to a relaxation response which was then abolished after administration of propranolol. Acetylcholine elicited contraction of the isolated detrusor muscle strip, and this was abolished in the presence of atropine These results suggest that the rabbit detrusor muscle is innervated by both cholinergic and adrenergic fibers and that the detrusor muscle contains cholinergic receptors as well as adrenergic a-and b-ones. Contrary to the popular opinion that the detrusor muscle predominantly contains adrenergic b-receptors, it seems likely that the adrenergic receptors differ in predominancy of either a or b which elicits contraction or relaxation, respectively, according to different areas of the muscle.

Responses of the Detrusor Muscle Strips of the Amyda Japonica and the Rabbit to some Autonomic Drugs / 대한비뇨기과학회지

Recent reports suggest that the responses of the detrusor muscle to the hypogastric nerve stimulation and some autonomic drugs may not be identical among various species. In this study, the responses of the isolated detrusor muscle strips of the Amyda Japonica and the rabbit to catecholamines were compared, and the type of the adrenergic-receptors was investigated. The results obtained were as follows : 1. Catecholamines (norepinephrine and epinephrine) evoked only contraction in the isolated detrusor muscle of the Amyda Japonica and relaxation in the preparation of the rabbit. 2. The contraction-response in the Amyda Japonica was blocked in the presence of regitine, an adrenergic alpha-receptor blocking agent. 3. The relaxation-response in the rabbit was abolished by pre-treatment with propranolol, an adrenergic beta-receptor blocking agent. 4. Acetylcholine elicited contraction in both of the isolated detrusor muscle strips of the Amyda japonica and the rabbit, and the response was completely blocked in the presence of atropine. 5. The results described above suggest that catecholamines exert excitatory effect on the detrusor muscle of the Amyda japonica as it contains adrenergic alpha-receptors and inhibitory effect on the same preparation of the rabbit as it contains the adrenergic beta-receptors. Key Word : amyda japonica,alpha receptor, beta receptor.