Hardy S G, Holmes D E
Department of Anatomy, University of Mississippi Medical Center, Jackson 39216.
Exp Brain Res. 1988;73(2):249-55. doi: 10.1007/BF00248217.
In 41 rats, bipolar electrical stimulation was administered to various regions of the frontal cortex, including the medial prefrontal cortex (MPFC), lateral prefrontal cortex (LPFC), infralimbic cortex, and convexity cortex. Resulting alterations of blood pressure and heart rate were noted. It was observed that hypotension resulted from stimulation administered to either LPFC, infralimbic cortex or ventral portion of MPFC (i.e. prelimbic cortex). Furthermore, stimulation of the LPFC typically produced bradycardia, whereas stimulation of the MPFC or infralimbic cortex had little or no effect on heart rate. Pharmacological and surgical blocks of the vagus nerves failed to attenuate the stimulus produced hypotension (SPH), as elicited from the prefrontal or infralimbic cortices, thus demonstrating that SPH in rats is not mediated by the vagus nerves. However, intraperitoneal injections of norepinephrine, which mimicked a state of increased sympathetic tone, were observed to completely block SPH. Accordingly, it is suggested that SPH may occur as the result of sympathetic inhibition. Furthermore, intravenous injections of naloxone were also observed to also completely block SPH, thus demonstrating that SPH may be mediated via opioid pathways.
对41只大鼠的额叶皮质不同区域，包括内侧前额叶皮质（MPFC）、外侧前额叶皮质（LPFC）、边缘下皮质和凸面皮质进行双极电刺激。记录由此引起的血压和心率变化。观察到，对LPFC、边缘下皮质或MPFC腹侧部分（即前边缘皮质）进行刺激会导致低血压。此外，刺激LPFC通常会引起心动过缓，而刺激MPFC或边缘下皮质对心率影响很小或没有影响。迷走神经的药理学和手术阻断未能减弱前额叶或边缘下皮质引发的刺激诱导性低血压（SPH），从而表明大鼠中的SPH不是由迷走神经介导的。然而，观察到腹腔注射去甲肾上腺素（模拟交感神经张力增加的状态）可完全阻断SPH。因此，有人提出SPH可能是交感神经抑制的结果。此外，还观察到静脉注射纳洛酮也可完全阻断SPH，从而表明SPH可能通过阿片类途径介导。
