Activation of anti- and pro-nociceptive mechanisms by front paw shock in spinal mice: involvement of humoral factors.
The effect of prolonged, intermittent front paw shock on nociception was studied in two groups of differently spinalized mice. The animals, spinalized so that the dura was left intact to allow free cerebrospinal fluid (CSF) passage, exhibited post-foot shock increase in latencies of spinally-mediated nociceptive reflexes. This anti-nociception was completely blocked by naloxone. A facilitation of nociceptive reflexes was observed in animals in which the spinal cord was ligated together with the dura. The results indicate that: front paw shock in mice leads to activation of supraspinal sites which mediate anti-nociception by releasing substance(s) reaching the spinal cord via the CSF route; single stressors may simultaneously activate both anti- and pro-nociceptive mechanisms.
Marek
P
P
Panocka
I
I
Sadowski
B
B
D000818:Animals; D003655:Decerebrate State / Q000134:cerebrospinal fluid; D004597:Electroshock; D018409:Foot Injuries; D051379:Mice; D009270:Naloxone; D018377:Neurotransmitter Agents / Q000134:cerebrospinal fluid*; D009619:Nociceptors / Q000502:physiology; D010146:Pain / Q000134:cerebrospinal fluid* / Q000503:physiopathology; D012018:Reflex / Q000502:physiology; D012684:Sensory Thresholds; D013116:Spinal Cord / Q000503:physiopathology
D018377:Neurotransmitter Agents; D009270:Naloxone