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ISSN Druckformat: 2155-014X
ISSN Online: 2155-0158
Electrical Activity of Neurons in the Primary Cultures of Trigeminal Ganglion
ABSTRAKT
The firing properties of small neurons (with diameters of soma less than 25 μm) in primary culture of the trigeminal ganglion (TG) of postnatal rats were investigated using patch-clamp technique in whole-cell configuration. TG neurons were divided into three groups according to their firing responses to long-lasting depolarizing pulses: adaptive neurons (AN) characterized by strongly adaptive responses; tonic neurons (TN) characterized by a multiple tonic firing; and neurons with a delay before initiation of AP generation, namely, NDG, AN, TN, and NDG. Those neurons also differed in AP electrophysiological and pharmacological characteristics. The TNs were distinguished by responses to hyperpolarization and the greatest value of input resistance. The TN, AN, and NDG were characterized by different active properties (amplitude of action potential and afterhyperpolarization, reobase, threshold). Each group of neurons was characterized by heterogeneity of AP duration and frequency properties for TN. The application of tetrodotoxin (TTX) (250 nM) resulted in full or partial inhibition of AP generation, and some neurons demonstrated TTX – insensitive firing responses. Neurons that were not affected by TTX had markedly longer AP. TTX had no effect on electrical activity of some AN and NDG. Based on the sensitivity to TTX and their electrophysiological properties, AN and NDG seem to be C-fiber nociceptors.