Calcium Currents and GABA sub(B) Receptors in the Dorsal Sensory Cells of the Lamprey Spinal Cord

Patch-clamp studies were performed on the isolated dorsal sensory cells of the spinal cords of three species of lamprey, Ichthyomyzon unicuspis, Petromyzon marinus, and Lampetra fluviatilis, to measure changes in the amplitudes of calcium current induced by GABA and its specific antagonists and agon...

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Bibliographic Details
Published in:Neuroscience and behavioral physiology 1999-02, Vol.29 (1), p.67-77
Main Authors: Batueva, I V, Buchanan, J T, Tsvetkov, E A, Sagatelyan, A K, Veselkin, N P
Format: Article
Language:English
Subjects:
dorsal sensory cells
Ichthyomyzon unicuspis
Lampetra fluviatilis
Petromyzon marinus
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Summary:Patch-clamp studies were performed on the isolated dorsal sensory cells of the spinal cords of three species of lamprey, Ichthyomyzon unicuspis, Petromyzon marinus, and Lampetra fluviatilis, to measure changes in the amplitudes of calcium current induced by GABA and its specific antagonists and agonists. The experiments showed that GABA (4 mM) reduced the peak amplitude of the calcium current by 28.5 plus or minus 4.9%, with subsequent recovery to 96.2 plus or minus 9.2% of control (n = 45). The GABA sub(B) agonist baclofen had similar effects. The GABA sub(A) agonists glycine and taurine had no effect on the Ca super(2+) current. The inhibitory effect of GABA was blocked by 2-hydroxysaclofen (a GABA sub(B) antagonist), but persisted in the presence of bicuculline (a GABA sub(A) dorsal sensory cellssantagonist). These results are evidence that the membranes of dorsal sensory cells contain GABA sub(B) receptors, which significantly increases our understanding of the mechanisms of presynaptic inhibition in the spinal cords of the cyclostomata.
ISSN:0097-0549