취장 및 간장 외분비기능에 대한 교감신경성 영향

Abstract

[한글]

취장 및 간장 외분비기능이 신경과 홀몬의 지배를 다같이 받고 있음은 잘 알려진 사실이다. 신경성지배에 있어 미주신경의 효과는 비교적 뚜렷하여 많은 연구가 이루어졌으나 취선의 교감신경성 영향은 일정치 않을 뿐 아니라 중요한 역할을 못한다고 보고 있다. 교감신경자극 또는 교감신경성 약물은 대체로 취 외분비기능을 억제시킨다고 하나 고양이에서 효소분비 증가를 초래한다는 보고도 있다.

근래 catecholamine중 dopamine은 개 취장에서 취액분비를 항진시킨다고 하며 dopamine의 대사산물인 6-hydroxydopamine은 화학적 교감신경절단제로 주목을 끌고 있다.

본 실험에서는 취 외분비 및 담즙분비의 감신경성 영향을 검색하고자 내인성catecholamine함량을 증감시켜 외분비 기능의 변동여부를 검토하고 아울러 dopamine의 상호작용 및 부교감신경의 영향을 관찰하였다.

실험동물로는 몸무게 200g 안팎의 흰쥐와 8kg 안팎의 잡종 개를 사용하였으며 secobarbital (30㎎/㎏)로 마취하였다. 담취관 또는 취관에 polyethylene tube를 삽입한 후 흰쥐는 2시간, 개는 10분간 분비액을 채취하였다. 흰쥐 실험은 대조군, 교감신경계 실험군 및

부교감신경계 실험군으로 크게 나누었으며 대조군은 생리적 식염수(ml/kg)를 복강내 주사하였다. 교감신경계 실험은 tranylcypromine (10mg/kg, i.p.), reserpine (2mg/kg, i.p.) 또는 6-hydroxydopamine (20 mg/ kg, i.p.)을 처치하여 실시하였으며 dopamine (0.1 mg/kg, i.m.)은 단독 또는 위의 약물과 병용투여 하였다. 부교감신경계 실험군에는 neostigmine (0.2 mg/kg, i.m.) 또는 hemicholinium (20㎍/kg, i.p)을 처치하였다. 개에서 dopa

mine분비효과는 reserpine 전처치 유무에 따라 검색하였으며 secretin 또는 pancreozymin의 분비작용과 비교하였다.

실험성적을 요약하면 다음과 같다.

1. 체내 catecholamine 함량에 따라 취장 및 간장 외분비기능은 현저히 달라져 함량의 증가는 분비량 및 효소분비저하를, 함량 감소는 담취액, 효소분비 및 cholate배출의 의의있는 항진을 나타냈다.

2. Dopamine 및 6-hydroxydopamine은 흰쥐의 담취 외분비에 별 영향을 주지 못하였으나 개에서는dopamine투여, 특히 정맥내 단회투여로 취액 분비항진이 나타났으며 이 반응은 secretin 또는 pancreozymin과 상승(相乘)되어 나타났다.

3. 체내 acetylcholine함량의 증가는 흰쥐 취효소분비를 현저히 증가시키나 cholate분비에는 큰 변동이 없었다. Acetylcholine합성억제물질(hemicholinium)은 취장 및 간장 외

분비에 별변동을 나타내지 않았다.

이상의 성적을 종합하여 보면 취장이나 간장 외분비기능에 대한 신경성 관장에는 유사성이 많으며 두 외분비선 모두 정상상태에서는 교감신경의 역할이 잠재되어 있으나 체내 교감신경성 amine함량의 증가 또는 감소로 교감신경기능 불균형이 나타나면 취장 및 간장

외분비기능은 현저히 변동된다고 생각한다.

[영문]

It has been known that the exocrine functions of pancreas and liver are under nervous and hormonal control. Of the nervous control vagal effects are well documented, but the sympathetic role on exocrine pancreas is less clear and generally thought to be unimportant, since the results of the sympathetic stimulation are contradict. Stimulation of the splanchnic nerve and sympathomimetics caused to inhibit pancreatic secretory activity (Harper and Vass 1941, Rudick et al 1973) but in cat enhanced enzyme secretion was also reported (Barlow and his associate 1971, 1974).

Recently it was found that dopamine elicited profuse pancreatic flow in dog (Hashimoto et al 1971), and much interests were given to the 6-hydroxydopamine as an agent of chemical sympathectomy.

In the present study to delineate the adrenergic influence on external pancreatic and bile secretion, the pancreatico-biliary secretion was compared in rats with depleting or repleting their endogenous catecholamines. In pursuance of these findings the pancreatic secretion in reserpinized dogs has also been studied.

Female albino rats and mongrel dogs weighing about 200 g and 8 kg, respectively, were used as experimental animals. The animals anesthetized with secobarbital (30 mg/kg) were fixed and the pancreatico-biliary or pancreatic duct were explored.

After insertion of a fine polyethylene tube into the duct the pancreatico-biliary secretion in rat or pancreatic juice in dog was collected for 2 hours or 10 minutes, respectively. The rats were divided into three experimental groups, i. e., control, sympathetic and parasympathetic. Physiologic saline (1 ml/kg) was given intraperitoneally to the controls.

For experiments of sympathetic series one of following agents with or without dopamine was administered: tranylcypromine (10 mg/kg, i. p. 24 and 4 hours before), reserpine (2 mg/kg, i. p.24 hours before), 6-hydroxydopamine (20 mg/kg, i. p.24 hours before) and dopamine (0.1 mg/kg, i. m. 10 minutes before). An anticholinesterase, neostigmine (0.2 mg/kg, i. m. 10 minutes before) or acetylcholine synthesis b1ockade, hemicholinium (20㎍/kg, i. p. 24, hours and 30 minutes before)was treated for experiments of parasympathetic series.

The responses to dopamine, secretin and/or pancreozymin were compared in the dog with or without reserpinization (0.1 mg/kg, i.m. 48 and 24 hours before). Sumner's or Cherry and Crandall's method was employed for amylase or lipase activity analysis. Bilirubin and cholate ware measured in accordance with Magee et al and Irvin et al, respectively.

The results are summarized as follows.

1. The external secretory functions of pancreas and liver in rat were greatly influenced by intrinsic catecholamine content Repletion of catecholamine by tranylcypromine resulted in a marked decrease in the flow and the enzyme output from pancreas and liver, and depletion by reserpine showed a significant increase in the secretion. In reserpinized dog basal pancreatic flow was also increased.

2. Dopamine stimulated transiently the pancreatic flow of dog and the response was potentiated with secretin or pancreozymin. But it has little effect on the secretory function of rat, and 6-hydroxydopamine failed to affect on exocrine function of pancreas and liver.

3. Cholinesterase inhibition caused a marked increase in enzyme output with little changes of the flow. The exocrine function was not affected by synthesis blockade of acetylcholine in rat.

It is conceived that the adrenergic control of exocrine pancreas and liver is quiescent in physiologic state, however, the sympathetic imbalance due to excess or deficit of intrinsic catecholamine content causes a profound influence on the secretory functions.