Brown D R, Hildebrand K R, Parsons A M, Soldani G
University of Minnesota, College of Veterinary Medicine, Department of Veterinary Biology, St. Paul 55108.
Peptides. 1990 May-Jun;11(3):497-500. doi: 10.1016/0196-9781(90)90049-b.
The enteric neuropeptide galanin (GAL) increased the amplitude of spontaneous contractions in longitudinally oriented muscle strips and inhibited short-circuit current (Isc) elevations induced by transmural electrical stimulation (ES) of mucosal sheets from porcine jejunum in vitro. GAL-induced contractions (GAL EC50 = 9 nmol/l) were maximally 25% of those elicited by 10 mumol/l carbamylcholine and remained unaffected by atropine, tetrodotoxin, or tachyphylaxis to substance P. The presynaptic Ca2+ channel blocker, omega-conotoxin (0.1 mumol/l), inhibited GAL-induced contractions by 66%. GAL attenuated mucosal Isc elevations induced by ES with an IC50 = 13 nmol/l and at 0.1 mumol/l produced rapid decreases in basal Isc averaging 8 +/- 2 microA cm-1 in 77% of tissues examined. The alpha-adrenoceptor blocker phentolamine or the opiate antagonist naloxone did not alter tissue Isc responses to GAL. These results suggest that GAL modulates neuronal activity linked to secretomotor function in the porcine small intestine.
肠神经肽甘丙肽（GAL）可增加纵向肌条的自发收缩幅度，并抑制体外猪空肠黏膜片经壁电刺激（ES）诱导的短路电流（Isc）升高。甘丙肽诱导的收缩（甘丙肽半数有效浓度=9 nmol/L）最大为10 μmol/L氨甲酰胆碱诱导收缩的25%，且不受阿托品、河豚毒素或对P物质快速耐受性的影响。突触前Ca2+通道阻滞剂ω-芋螺毒素（0.1 μmol/L）可使甘丙肽诱导的收缩抑制66%。甘丙肽可减弱ES诱导的黏膜Isc升高，半数抑制浓度=13 nmol/L，在0.1 μmol/L时，77%受检组织的基础Isc迅速下降，平均为8±2 μA/cm²。α-肾上腺素能受体阻滞剂酚妥拉明或阿片拮抗剂纳洛酮不会改变组织对甘丙肽的Isc反应。这些结果表明，甘丙肽可调节与猪小肠分泌运动功能相关的神经元活动。
