Neuropeptide Y actions and the distribution of Ca2+-dependent Cl- conductance in rat dorsal root ganglion neurons.
Neuropeptide Y (NPY) increases the excitability of 'small', nociceptive, dorsal root ganglion (DRG) neurons. This effect, which may contribute to the etiology of 'neuropathic' pain, has been attributed to attenuation of Ca2+-sensitive K+ conductance(s) (gK,Ca) following suppression of Ca2+ entry via N-type Ca2+ channels. A problem arises with this conclusion because rat DRG neurons normally contain high intracellular Cl- and some of them express a Ca2+-dependent Cl- conductance (gCl,Ca). In this study, we find that in rat DRG neurons increasing intracellular Cl- does not attenuate the effect of 1 microM NPY because gCl,Ca is not found in 'small' DRG cells and the peptide failed to affect the gCl,Ca found in 'large' cells. Thus, the presence of gCl,Ca in a subpopulation of 'large' DRG neurons does not alter the conclusion that excitatory effects of NPY result from attenuation of gK,Ca.
Abdulla
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FA
Department of Physical Therapy, School of Allied Health Sciences Tennessee State University, Nashville 37909, USA.
Smith
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PA
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D019771:Axotomy; D002118:Calcium / Q000502:physiology*; D048429:Cell Size / Q000502:physiology; D002478:Cells, Cultured; D018118:Chloride Channels / Q000502:physiology*; D002712:Chlorides / Q000378:metabolism; D004594:Electrophysiology; D005727:Ganglia, Spinal / Q000166:cytology*; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology; D009408:Nerve Compression Syndromes / Q000503:physiopathology; D009475:Neurons, Afferent / Q000737:chemistry / Q000166:cytology / Q000502:physiology*; D009478:Neuropeptide Y / Q000494:pharmacology*; D009620:Nodose Ganglion / Q000166:cytology; D010146:Pain / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013564:Sympathetic Nervous System / Q000166:cytology / Q000503:physiopathology; D012668:Trigeminal Ganglion / Q000166:cytology
D018118:Chloride Channels; D002712:Chlorides; D009478:Neuropeptide Y; D002118:Calcium