Yohimbine reduces inhibition of lamina X neurones by stimulation of the locus coeruleus.
The effects of yohimbine, on inhibition of C-fibre evoked responses of spinal lamina X neurones by electrical stimulation of the locus coeruleus (LC) were studied in rats. LC stimulation inhibited by 67.33 +/- 25.14%, the C-fibre evoked responses in 24 out of 30 WDR neurones and the C-component of the flexion reflex by 77.62 +/- 18.77%. The A-fibre evoked responses with wide dynamic range (WDR) and low threshold (LT) neurones were not significantly affected by LC stimulation. After administration of yohimbine, LC-induced inhibition of lamina X neurones was attenuated by 77.43 +/- 23.22% without significant changes in C-fibre evoked responses. The results suggest that alpha 2-adrenoceptors may be involved in mediation of LC-induced inhibition on lamina X neurones.
Shanghai Brain Research Institute, Chinese Academy of Sciences.
W
W
Li
Z Q
ZQ
Zhao
D000818:Animals; D004558:Electric Stimulation; D008125:Locus Coeruleus / Q000166:cytology* / Q000187:drug effects; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects / Q000378:metabolism; D009413:Nerve Fibers, Myelinated / Q000187:drug effects; D009474:Neurons / Q000187:drug effects*; D009619:Nociceptors / Q000502:physiology; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology; D013116:Spinal Cord / Q000166:cytology* / Q000187:drug effects; D015016:Yohimbine / Q000494:pharmacology*
D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D009638:Norepinephrine