Capsaicin sensitivity and voltage-gated sodium currents in colon sensory neurons from rat dorsal root ganglia
| Autor: | G. F. Gebhart, Ruth E. Wachtel, Xin Su |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Male
Serotonin Adenosine Colon Physiology Action Potentials Pain Tetrodotoxin Pharmacology Bradykinin Dinoprostone Sodium Channels Rats Sprague-Dawley chemistry.chemical_compound Ganglia Spinal Physiology (medical) medicine Animals Neurons Afferent Fluorescent Dyes Analgesics Dose-Response Relationship Drug Hepatology Sodium Gastroenterology Carbocyanines Sensory neuron Rats Electrophysiology medicine.anatomical_structure Nociception chemistry Capsaicin Anesthesia Capsazepine Ion Channel Gating Histamine medicine.drug |
| Zdroj: | American Journal of Physiology-Gastrointestinal and Liver Physiology. 277:G1180-G1188 |
| ISSN: | 1522-1547 0193-1857 |
| DOI: | 10.1152/ajpgi.1999.277.6.g1180 |
| Popis: | DiI-labeled colon sensory neurons were acutely dissociated from S1 rat dorsal root ganglia (DRG) and studied using perforated whole cell patch-clamp techniques. Forty-six percent (54/116) of labeled sensory neurons responded to capsaicin (10− 8– 10− 5M) with an increase in inward current, which was a nonspecific cation conductance. Responses to capsaicin applied by puffer ejection were dependent on dose, with a half-maximal response at 4.9 × 10− 7 M; bath application was characterized by marked desensitization. Voltage-gated Na+currents in 23 of 30 DRG cells exhibited both TTX-sensitive and TTX-resistant components. In these cells, capsaicin induced an inward current in 11 of 17 cells tested. Of the cells containing only a TTX-sensitive component, none of six cells tested was sensitive to capsaicin. In all cells that responded to capsaicin with an increase in inward current, capsaicin abolished voltage-gated Na+currents ( n = 21). Capsazepine (10− 6 M) significantly attenuated both the increase in inward current and the reduction in Na+currents. Na+ currents were not significantly altered by adenosine, bradykinin, histamine, PGE2, or serotonin at 10− 6 M and 10− 5 M. These findings may have important implications for understanding both the irritant and analgesic properties of capsaicin. |
| Databáze: | OpenAIRE |
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