Abstract
The effect of 5-hydroxytryptamine (5-HT) on population primary afferent depolarisation (PAD) has been studied using in vitro spinal cord preparations from normal and capsaicin pre-treated (neonatal subcutaneous injection; 75 mg kg-1) rats aged 10-14 days. In preparations from untreated rats, the concentration-response curve for PAD in response to 0.1-100 μM 5-HT was bell-shaped but in the capsaicin pre-treated group, a non-saturating 5-HT- induced PAD concentration-response curve was generated. Quantitatively, the mean PAD responses to 0.1-10 μM 5-HT were of a greater amplitude in the control group compared to the capsaicin pre-treated group (p ≤ 0.05). For the highest 5-HT concentration of 100 μM, PAD values were significantly greater in the capsaicin pre-treated group (p ≤ 0.05). These data indicate that control of sensory afferent polarity may involve two 5-HT receptor types and that nociceptive and non-nociceptive afferents may be targets for released 5-HT.
Original language | English (US) |
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Pages (from-to) | 339-342 |
Number of pages | 4 |
Journal | Brain Research |
Volume | 789 |
Issue number | 2 |
DOIs | |
State | Published - Apr 13 1998 |
Externally published | Yes |
Bibliographical note
Funding Information:Supported by The Wellcome Trust. Technical assistance from J. Daniel and photography by D. Johanson.
Keywords
- Capsaicin
- GABA
- Nociceptive afferent
- Primary afferent depolarization
- Serotonin (5- HT)
- Spinal dorsal horn