Morse M A, Bell L, Rutlen D L
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06510.
Acta Physiol Scand. 1990 Mar;138(3):331-6. doi: 10.1111/j.1748-1716.1990.tb08854.x.
The direct influence of systemic muscarinic receptor stimulation on total splanchnic intravascular volume and the splanchnic organs responsible for the total splanchnic volume change associated with muscarinic receptor stimulation in the animal with an intact circulation are unknown. Furthermore, the subsequent effect of these volume changes on cardiac output is not known. Thus, acetylcholine was infused at 5 micrograms kg-1 min-1 in 25 anaesthetized dogs in which nicotinic blockade of the ganglia was achieved with mecamylamine, while total and regional splanchnic intravascular volume changes were determined with a radionuclide imaging technique. Total splanchnic volume decreased by 4.9 +/- 1.0% (P less than 0.0001), splenic volume decreased by 10.3 +/- 2.0% (P less than 0.0001), hepatic volume increased by 5.8 +/- 1.4% (P less than 0.01), extrahepatosplenic volume increased by 6.6 +/- 1.6% (P less than 0.01) and cardiac output increased from 1960 +/- 190 to 2290 +/- 230 ml min-1 (P less than 0.001). After splenectomy (n = 13), the hepatic and extrahepatosplenic volume increments were abolished, and the increase in cardiac output was not attenuated (1600 +/- 260 to 2040 +/- 370 ml min-1). After subsequent evisceration (n = 5), the cardiac output increment associated with acetylcholine was still not attenuated. Acetylcholine-associated splanchnic volume changes were abolished after muscarinic receptor blockade with atropine. Thus, muscarinic receptor stimulation causes a decrease in total splanchnic volume due entirely to a decrease in splenic volume. The splanchnic volume changes do not influence cardiac output.
在循环系统完整的动物中，全身毒蕈碱受体刺激对总内脏血管内体积以及与毒蕈碱受体刺激相关的总内脏体积变化所涉及的内脏器官的直接影响尚不清楚。此外，这些体积变化对心输出量的后续影响也不明确。因此，在25只麻醉犬中以5微克/千克·分钟-1的速度输注乙酰胆碱，这些犬通过美加明实现了神经节的烟碱样阻断，同时用放射性核素成像技术测定总内脏和局部内脏血管内体积变化。总内脏体积减少了4.9±1.0%（P<0.0001），脾体积减少了10.3±2.0%（P<0.0001），肝体积增加了5.8±1.4%（P<0.01），肝脾外体积增加了6.6±1.6%（P<0.01），心输出量从1960±190增加到2290±230毫升/分钟（P<0.001）。脾切除术后（n = 13），肝和肝脾外体积的增加被消除，但心输出量的增加并未减弱（从1600±260增加到2040±370毫升/分钟）。随后进行内脏切除术后（n = 5），与乙酰胆碱相关的心输出量增加仍然没有减弱。用阿托品阻断毒蕈碱受体后，与乙酰胆碱相关的内脏体积变化被消除。因此，毒蕈碱受体刺激导致总内脏体积减少完全是由于脾体积减小。内脏体积变化不影响心输出量。
