Neurotransmitter modulation of calcium current in rat spinal cord neurons.
The modulation of Ca2+ currents by neurotransmitters was studied in freshly dissociated rat spinal cord neurons, using the whole-cell patch-clamp technique. GABA, baclofen, adenosine, ATP, serotonin, norepinephrine, somatostatin, and dynorphin A inhibited the current through Ca2+ channels in a substantial fraction of cells, while substance P, vasoactive intestinal polypeptide, [D-ala2,d-leu5]-enkephalin, cholecystokinin-8 (sulfated), calcitonin gene-related peptide, angiotensin II, neurotensin, vasopressin, and thyrotropin-releasing hormone had no effect. In the case of baclofen, the inhibition is mediated, at least in part, by a GTP-binding protein. Suppression of Ca2+ current by neurotransmitters may represent a mechanism of presynaptic inhibition in the spinal cord.
Sah
D W
DW
Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115.
D000818:Animals; D001464:Barium / Q000502:physiology; D001696:Biomechanical Phenomena; D015220:Calcium Channels / Q000502:physiology*; D002478:Cells, Cultured; D004553:Electric Conductivity; D009474:Neurons / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D051381:Rats; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism*
D015220:Calcium Channels; D018377:Neurotransmitter Agents; D001464:Barium