McKitrick D J, Calaresu F R
Department of Physiology, University of Western Ontario, London, Canada.
J Auton Nerv Syst. 1991 Jan;32(1):69-75. doi: 10.1016/0165-1838(91)90237-w.
As microinjection of either substance P (SP) or acetylcholine (ACh) into the right intermediolateral cell nucleus (IML) at the T2 level elicits increases in heart rate (HR) in the anesthetized rat, we investigated the possibility of a synergistic effect on HR and arterial pressure (AP) of ACh and SP microinjected in this nucleus. Moreover, we studied the effect on HR and AP of microinjection of either ACh or SP into the IML combined with activation of cardiovascular neurons in the ipsilateral rostral ventrolateral medulla (RVLM) by microinjection of glutamate (Glu). Male Wistar rats (n = 16) were anesthetized with urethane (1.4 g/kg i.p.), artificially ventilated, and the dorsal medulla and spinal cord (T1-T3) were exposed. Micropipettes containing SP and ACh were positioned in the right IML at the T2 level. Microinjection of threshold amounts of ACh (5 x 10(-2) M, 2-10 nl) and SP (3 x 10(-6) M, 2-10 nl) that caused small or no changes in HR or AP (less than 10 bpm or mmHg) elicited statistically significant synergistic increases in HR (22.9 +/- 3.3 bpm) but no changes in AP. Threshold microinjections of Glu (0.18 M, 2-10 nl) into the right RVLM combined with microinjections of threshold amounts of SP or ACh into the ipsilateral IML elicited significant synergistic increases in HR of 13.1 +/- 1.9 bpm and 10.6 +/- 1.9 bpm and in AP of 9.7 +/- 1.9 mmHg and 10.8 +/- 1.7 mmHg, respectively. These results indicate that SP and ACh interact to influence cardioacceleratory spinal preganglionic neurons (SPN) and interact with the transmitter released in the IML by RVLM stimulation to elicit increases in HR.(ABSTRACT TRUNCATED AT 250 WORDS)
由于向麻醉大鼠T2水平的右侧中间外侧细胞核（IML）微量注射P物质（SP）或乙酰胆碱（ACh）均可引起心率（HR）升高，我们研究了在此核内微量注射ACh和SP对HR和动脉血压（AP）产生协同作用的可能性。此外，我们还研究了向IML微量注射ACh或SP并通过微量注射谷氨酸（Glu）激活同侧延髓头端腹外侧区（RVLM）的心血管神经元对HR和AP的影响。雄性Wistar大鼠（n = 16）用乌拉坦（1.4 g/kg腹腔注射）麻醉，进行人工通气，暴露延髓背侧和脊髓（T1 - T3）。将含有SP和ACh的微吸管置于T2水平的右侧IML。微量注射阈剂量的ACh（5×10⁻² M，2 - 10 nl）和SP（3×10⁻⁶ M，2 - 10 nl），这些剂量引起HR或AP微小变化或无变化（小于10次/分或mmHg），可引起HR有统计学意义的协同升高（22.9±3.3次/分），但AP无变化。向右侧RVLM微量注射阈剂量的Glu（0.18 M，2 - 10 nl）并联合向同侧IML微量注射阈剂量的SP或ACh，分别引起HR显著协同升高13.1±1.9次/分和10.6±1.9次/分，AP升高9.7±1.9 mmHg和10.8±1.7 mmHg。这些结果表明，SP和ACh相互作用影响心脏加速脊髓节前神经元（SPN），并与RVLM刺激在IML释放的递质相互作用，引起HR升高。（摘要截断于250字）
