[The influence of electroacupuncture with different frequencies on the discharges of neurons in rostral ventromedial medulla on rats].
The experiments were carried out on rats, anesthetized with urethan and paralyed with tubocuraine. Stainless steel needles were inserted into bilateral "Zusanli" points. The unit discharges of RVM neurons were recorded extracellalarly by microelectrode. The searching of nociceptive neurons and processing of data were operated automatically by a real time control system. The results were as follow: 1. The pain response of excitatory neurons could be inhibited by 2 Hz EA (n = 15/22, P < 0.01), the mean inhibition rate was 32.40%. 2. The inhibitory effects of 2 Hz were completely blocked by naloxone pretreated (n = 5/5, P < 0.01). 3. The pain response of excitatory neurons could be inhibited by 10 Hz EA(n = 10/13, P < 0.01), the mean inhibition rate was 49.06%. 4. The inhibitory effects of 10 Hz EA were partially blocked by naloxone pretreated (n = 5/5, P < 0.01). 5. Both 2 Hz and 10 Hz EA could enhance the spontaneous discharges of excitatory neurons in RVM, and the percentage of change in the frequency was 62.45% and 112.02% respectively. 6. Neither 2 Hz nor 10 Hz EA could obviously influence the spontaneous activity of inhibitory neurons in RVM. The results suggest that both 2 Hz and 10 Hz EA could activate excitatory neurons in RVM, which may suppress nociceptive transmission via opioid mechanism.
Ao
M
M
Department of Physiology, Hubei Medical University, Wuhan.
Wei
J
J
Tan
Z
Z
Hu
Q
Q
Tang
J
J
D015667:Acupuncture Analgesia; D000818:Animals; D004594:Electrophysiology; D005260:Female; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009619:Nociceptors / Q000502:physiology*; D051381:Rats