Objectives To investigatethe effects and involved mechanisms of scopolamine(Scop) on rabbit ear blood vessels. Methods Rabbitear blood vessels were desympathetic and desensoryinnervation with surgical operation. Diame...Objectives To investigatethe effects and involved mechanisms of scopolamine(Scop) on rabbit ear blood vessels. Methods Rabbitear blood vessels were desympathetic and desensoryinnervation with surgical operation. Diameters of dor-sal auricular arterial trunks in vivo were measuredwith a pair of compasses and the ruler in a dissectingmicroscope, and effluents from isolated ear underconstant perfusion pressure were recorded with a digi-tal drop-recorder. Results Intramuscular injectionof Scop 0.1 mg/kg made the diameter of denerveddorsal auricular arterial trunks, as well as that of in-nerved ones, significantly increased. Scop by itself,atthe maximal concentration (Cmax) of 3μM, 30μMand 300μM, did not alter the effluent flow from theisolated denervated rabbit ear, but chlorpromazine(CPZ), at Cmax of 1μM, acetylcholine (ACh), 0.25μM, all significantly increased the effluent flow, andnorepinephrine (NE), 0.1μM, significantly decreasedthe effluent. Scop, 3μM, did not affect ACh (0.25μM)-induced the increase of effluent flow, but Scop,30μM, alleviated the increase. Scop, 3μM, did notaffect NE (0.1μM)-induced the decrease of effluentflow, but Scop, 10, 30 and 100μM, significantly alle-viated the decrease. Conclusions The study sug-gests that Scop has no direct vasodilator effect. Thevasodilator effect of Scop is not due to the blockade ofmuscarinic receptor. However, Scop can dilate bloodvessels contracted by α_1-adrenoceptor activation.展开更多
文摘Objectives To investigatethe effects and involved mechanisms of scopolamine(Scop) on rabbit ear blood vessels. Methods Rabbitear blood vessels were desympathetic and desensoryinnervation with surgical operation. Diameters of dor-sal auricular arterial trunks in vivo were measuredwith a pair of compasses and the ruler in a dissectingmicroscope, and effluents from isolated ear underconstant perfusion pressure were recorded with a digi-tal drop-recorder. Results Intramuscular injectionof Scop 0.1 mg/kg made the diameter of denerveddorsal auricular arterial trunks, as well as that of in-nerved ones, significantly increased. Scop by itself,atthe maximal concentration (Cmax) of 3μM, 30μMand 300μM, did not alter the effluent flow from theisolated denervated rabbit ear, but chlorpromazine(CPZ), at Cmax of 1μM, acetylcholine (ACh), 0.25μM, all significantly increased the effluent flow, andnorepinephrine (NE), 0.1μM, significantly decreasedthe effluent. Scop, 3μM, did not affect ACh (0.25μM)-induced the increase of effluent flow, but Scop,30μM, alleviated the increase. Scop, 3μM, did notaffect NE (0.1μM)-induced the decrease of effluentflow, but Scop, 10, 30 and 100μM, significantly alle-viated the decrease. Conclusions The study sug-gests that Scop has no direct vasodilator effect. Thevasodilator effect of Scop is not due to the blockade ofmuscarinic receptor. However, Scop can dilate bloodvessels contracted by α_1-adrenoceptor activation.
