Endothelin-1-induced priming to capsaicin in young animals.
Endothelin-1 (ET-1) is a known algogen that causes acute pain and sensitization in humans and spontaneous nociceptive behaviors when injected into the periphery in rats. This study sought to examine the effect of ET-1 exposure in the neonatal period on subsequent contralateral capsaicin-induced secondary mechanical hyperalgesia. ET-1 or saline was injected into the left plantar hindpaw on postnatal day 7 (P7). On postnatal day 11 (P11), capsaicin cream or control lotion was applied to the right dorsum hind paw and mechanical paw withdrawal thresholds were measured in the plantar hind paw. In saline control males, P11 administration of capsaicin produced a secondary mechanical hyperalgesia that was still present at 2h. Neonatal priming with ET-1 did not alter the magnitude or the duration of secondary mechanical hyperalgesia in males. In contrast, in control females, P11 administration of capsaicin produced less than 40 min of mechanical hyperalgesia. Neonatal priming with ET-1 prolonged the duration of secondary mechanical hyperalgesia in females. Priming with ET-1 on P7 led to a significant increase in capsaicin-induced Fos expression in the dorsal horn of the spinal cord in both males and females compared to controls (p<0.001). These findings further suggest that pain in early life may alter future responses to painful stimuli at both the behavioral and neuronal level.
['Smith|Terika|T|', 'Beasley|Sarah|S|', 'Smith|Sherika|S|', 'Mark|Isiasha|I|', 'Sweitzer|Sarah M|SM|']
D000818:Animals D000831:Animals, Newborn D002211:Capsaicin D019332:Endothelin-1 D005260:Female D007839:Functional Laterality D006930:Hyperalgesia D008297:Male D017288:Pain Threshold D010812:Physical Stimulation D020671:Posterior Horn Cells D016760:Proto-Oncogene Proteins c-fos D017207:Rats, Sprague-Dawley D012737:Sex Factors D014110:Touch
Capsaicin Endothelin-1 (ET-1) Nociception Neonatal rat