Electroacupuncture at P5-6 acupoints significantly increased the nucleus raphé pallidus neuronal response to splanchnic nerve stimulation from 3 to 10 spikes/30 stim, an effect blocked by kynurenic acid.
Does electroacupuncture at P 5-6 acupoints reduce cardiovascular sympathoexcitatory reflexes via a pathway involving the ventrolateral periaqueductal gray and nucleus raphé pallidus in anesthetized cats?
Electroacupuncture inhibits cardiovascular sympathoexcitatory reflexes through a central neural pathway involving the ventrolateral periaqueductal gray and the nucleus raphé pallidus.
Absolute Event Rate: 10% vs 3%
p-value: p=<0.05
We have shown that electroacupuncture (EA) inhibits sympathoexcitatory rostral ventrolateral medulla (rVLM) neurons and reflex responses following activation of a long-loop pathway in the arcuate nucleus and ventrolateral periaqueductal gray (vlPAG). Additionally, EA at P 5-6 acupoints (overlying the median nerve) activates serotonin-containing neurons in the nucleus raphé pallidus (NRP), which, in turn, inhibit rVLM neurons. Although direct projections from the vlPAG to the rVLM exist, it is uncertain whether an indirect pathway through the NRP serves an important role in vlPAG-rVLM cardiovascular modulation. Therefore, the splanchnic nerve (SN) was stimulated to induce cardiovascular sympathoexcitatory reflexes, and EA was applied at P 5-6 acupoints in α-chloralose-anesthetized cats. A single-barreled recording electrode was inserted into the NRP or rVLM. Microinjection of DL-homocysteic acid (DLH) into the vlPAG increased the NRP neuronal response to SN stimulation (5 ± 1 to 12 ± 2 spikes/30 stim). Likewise, EA at P 5-6 for 30 min increased the NRP response to SN stimulation (3 ± 1 to 10 ± 2 spikes/30 stim), an effect that could be blocked by microinjection of kynurenic acid (KYN) into the caudal vlPAG. Furthermore, the reflex increase in blood pressure induced by application of bradykinin to the gallbladder and the rVLM cardiovascular presympathetic neuronal response to SN stimulation was inhibited by injection of DLH into the vlPAG, a response that was reversed by injection of KYN into the NRP. These results indicate that EA activates the vlPAG, which excites the NRP to, in turn, inhibit rVLM presympathetic neurons and reflex cardiovascular sympathoexcitatory responses.
Li et al. (Thu,) conducted a other in Cardiovascular sympathoexcitatory reflexes (Animal model). Electroacupuncture at P5-6 acupoints vs. Pre-stimulation baseline / Saline vehicle was evaluated on Nucleus raphé pallidus (NRP) neuronal response to splanchnic nerve stimulation (spikes/30 stim) (p=<0.05). Electroacupuncture at P5-6 acupoints significantly increased the nucleus raphé pallidus neuronal response to splanchnic nerve stimulation from 3 to 10 spikes/30 stim, an effect blocked by kynurenic acid.