Abstract
The catecholamine concentration and the amount of α-adrenergic receptor in aganglionic colon were measured and responses to electrical field stimulation were investigated in order to elucidate the pathophysiology of the aganglionic segment in Hirschsprung's disease. The catecholamine concentration was measured by high performance liquid chromato-graphy with electrochemical detection, which was found to be more accurate than histochemical or fluorometric method. Norepinephrine (NE) concentration in the aganglionic colon was appoximately two times greater than in the normal colon. NE in the ganglionic colon was 300.2±120.3ng/g(n=7) in contrast to 623.3±300.Ong/g (n=7) in the aganglionic segment of Hirschsprung's disease. On the other hand, no significant difference was found in the amount of other two catecholamines; epinephrine and dopamine. In extensive aganglionosis, NE concentration differed for each part of the colon; 295.1±91.6ng/g (n=4) in the ascending, 326.8±122.9ng/g (n=4) in the transverse, 489.8±221.8ng/g (n=4) in the descending and 693.4±355.Ong/g (n=4) in the recto-sigmoid colon. α-adrenergic receptor was assayed by measuring the specific binding activity of 3^H-dihydro-α-ergocryptine. The ganglionic colon contained 196f mol/mg prot. receptor sites and the aganglionic segment had 207f mol/mg prot.. There was no significant difference between the two segments of the colon in Hirschsprung's disease. Response to electrical field stimulation was also investigated to evaluate the existence of neuro-muscular junction in the aganglionic colon. The aganglionic segment showed only cholinergic contraction, whereas, non-adrenergic relaxation was dominant in the normal colon. From the results of the studies, it is confirmed that in Hirschsprung's disease, cholinergic innervation and the absence of the non-adrenergic inhibitory nerve cause the contractile state, and even NE concentration is much higher than normal colon.
