[Proprioceptive and cutaneous evoked somatosensory potentials in the baboon: cycles of GABAergic excitability and inhibition].
Double stimulations induce deep and long-lasting inhibition (0-300 ms) of the P16-N30 components of somatosensory potentials (SEP) evoked by sciatic or sural nerve stimulation. This inhibition is evidenced on both S1 and M1 cortical areas, demonstrating similar course and duration, whatever the source (right or left limb) and/or the modality (extero- or proprioceptive) of conditioning and testing afferences. The depth of this inhibition depends on the relative amplitude of the conditioning to testing SEP. After muscle injection of a subconvulsive dose of bicuculline, tSEPs are facilitated when individually elicited. When double stimulations are used, the inhibition of the SEP test is sharply reduced (with a 30-ms interstimulus delay). However, disinhibition of the conditioned SEP does not depend on separate individual SEP facilitations. Cortical GABAergic type a circuits are likely to be involved in inhibition of the conditioned SEP. This inhibition would be a non-invasive image of inhibitions that preserve the specificities of sensory messages in primary areas.
el Kharroussi
M
M
Université Hassan II Ain Chock, faculté des Sciences I, Département de biologie, Maarif, Casablanca, Maroc.
Françon
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D
Benjelloun
W
W
Hugon
M
M
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D004558:Electric Stimulation; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects / Q000502:physiology*; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D010215:Papio; D011434:Proprioception / Q000502:physiology*; D012584:Sciatic Nerve / Q000502:physiology; D012867:Skin / Q000294:innervation*; D013497:Sural Nerve / Q000502:physiology; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D018756:GABA Antagonists; D005680:gamma-Aminobutyric Acid; D001640:Bicuculline
Potentiels évoqués somesthésiques proprioceptifs et cutanés chez le babouin: cycles d'excitabilité et inhibitions GABAergiques.