A subset of periglomerular neurons in the rat accessory olfactory bulb may be excited by GABA through a Na(+)-dependent mechanism.
The periglomerular (PG) cells of the accessory olfactory bulb (AOB) are GABAergic interneurons which receive input from the vomeronasal sensory neurons and form dendrodendritic synapses with each other and with mitral cells. Their electrophysiological properties have not been investigated. We have developed a novel method of isolating PG cells from the AOB, and used the whole-cell patch and gramicidin-perforated patch clamp techniques to measure their basic electrophysiological characteristics and their response to GABA. PG cells were found to be excitable neurons with voltage-gated Na(+) and K(+) currents, though it was very difficult to get PG cells to fire an action potential. The voltage-gated Na(+) currents of PG cells activate at more positive potentials than those of typical CNS neurons. PG cells respond to GABA with currents in which GABA(A) receptors play a significant role. A subset ( approximately 40%) of PG cells respond to GABA with currents which have unusually high reversal potentials, indicating that GABA may be excitatory to these neurons. This phenomenon cannot be explained entirely by elevation of intracellular chloride concentrations, and is dependent on the presence of extracellular sodium.
Goldmakher
G V
GV
Department of Physiology, UT Southwestern Medical Center, 75235, Dallas, TX, USA. goldmakh2utsw.swmed.edu
Moss
R L
RL
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002469:Cell Separation; D005260:Female; D006096:Gramicidin; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D009830:Olfactory Bulb / Q000166:cytology* / Q000502:physiology; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000502:physiology; D051381:Rats; D011963:Receptors, GABA-A / Q000502:physiology; D012964:Sodium / Q000502:physiology*; D026941:Sodium Channel Blockers; D015222:Sodium Channels / Q000502:physiology; D019789:Tetraethylammonium / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D026902:Potassium Channel Blockers; D015221:Potassium Channels; D011963:Receptors, GABA-A; D026941:Sodium Channel Blockers; D015222:Sodium Channels; D006096:Gramicidin; D013779:Tetrodotoxin; D005680:gamma-Aminobutyric Acid; D019789:Tetraethylammonium; D012964:Sodium