Collagen Metabolism and Pressure sore, and its prevention

研究了腺苷受体激动剂对麻醉犬胰腺外分泌的影响。选择性腺苷A_<2A>受体激动剂CGS21680的分级剂量（1-300 nmol/kg）产生剂量依赖性的胰液分泌率增加，最大效应约为30 nmol/kg。选择性腺苷A_1受体激动剂CPA （1 ~ 300 nmol/kg）不引起胰腺分泌。CGS21680 （3 ~ 30 nmol/kg）和分泌素（0.01 ~ 0.03 pmol/kg）使胰液中碳酸氢盐浓度升高，蛋白质浓度降低。DMPX （5-50 nmol/kg）是一种弱腺苷A_<2A>受体拮抗剂，可引起cgs21680诱导的胰腺分泌的剂量-反应曲线逐渐平行向右移动，但最大反应没有改变。选择性A_1腺苷受体拮抗剂DPCPX （100 nmol/kg）对cgs21680诱导的胰腺分泌无拮抗作用。这些结果表明，狗胰腺外分泌细胞中存在腺苷A_<2A>受体，参与水和碳酸氢盐的分泌反应。

Effects of adenosine receptor agonists of the pancreatic exocrine secretion were examined in anesthetized dogs. Graded doses of CGS21680 (1-300 nmol/kg), a selective adenosine A_<2A> receptor agonist, produced dose-dependent increasein the secretory rate of pancreatic juice, with a maximum effect at approximately 30 nmol/kg. However, CPA (1-300 nmol/kg), a selective adenosine A_1 receptor agonist, did not cause the pancreatic secretion. CGS21680 (3-30 nmol/kg) and secretin (0.01-0.03 pmol/kg) increased the bicarbonate concentration in pancreatic juice and decreased the protein concentration. DMPX (5-50 nmol/kg), a weak adenosine A_<2A> receptor antagonist, caused a progressive parallel shift to the right in the dose -response curve for CGS21680-induced pancreatic secretion without changes in the maximal response. DPCPX (100 nmol/kg), a selective A_1 adenosine receptor antagonist, did not antagonize the CGS21680-induced pancreatic secretion. These results suggest the existence of adenosine A_<2A> receptors in the exocrine cells of dog pancreas, involved in the water and bicarbonate secretory response.