Involvement of serotonin in the enhancement of the rat spinal excitability by high pressures.
Using an electrical stimulation of the reticulospinal tract at the level of the medial longitudinal fasciculus, the effects, and the neurochemical mechanisms of these effects, of a progressive increase in helium-oxygen pressures, up to 50 bar, on the spinal cord excitability in the chronic rat are investigated. In control animals, high pressure exposure over 30 bar was found to increase markedly the electromyogram response evoked in nuchal muscles. This startlelike response was monosynaptically induced by stimulation of the reticulospinal tract. Conversly, no hyperbaric alteration in spinal excitability has been observed in animals pretreated with the classical 5-HT antagonist drug metergoline. These results emphasize the importance of spinal cord as a potential target for mediating hyperbaric effects on sensorimotor behaviors (i.e., motor disturbances of the HPNS). Moreover, our work suggests that serotonin could be implicated in hyperbaric spinal cord hyperexcitability.
David
J M
JM
Laboratoire de Neurophysiologie Pharmacologique, Université de Provence, UA CNRS 372, Marseille, St-Jérôme, France.
Risso
J J
JJ
Pellet
J
J
D000818:Animals; D001933:Brain Stem / Q000187:drug effects / Q000502:physiology; D002493:Central Nervous System Diseases / Q000503:physiopathology*; D004558:Electric Stimulation; D006610:High Pressure Neurological Syndrome / Q000503:physiopathology*; D008297:Male; D008711:Metergoline / Q000494:pharmacology; D011312:Pressure; D051381:Rats; D013216:Reflex, Startle / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000502:physiology*; D013116:Spinal Cord / Q000187:drug effects / Q000502:physiology*
D008711:Metergoline; D012701:Serotonin