title: Endothelin-1-induced priming to capsaicin in young animals.
abstract: 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.
authors.affiliation: Department of Pharmacology, Physiology and Neuroscience, University of South Carolina, Columbia, SC, United States. Electronic address: Terika.Smith@uscmed.sc.edu.
authors.forename: Terika
authors.initials: T
authors.lastname: Smith
authors.affiliation: Department of Pharmacology, Physiology and Neuroscience, University of South Carolina, Columbia, SC, United States.
authors.forename: Sarah
authors.initials: S
authors.lastname: Beasley
authors.affiliation: Department of Pharmacology, Physiology and Neuroscience, University of South Carolina, Columbia, SC, United States.
authors.forename: Sherika
authors.initials: S
authors.lastname: Smith
authors.affiliation: Department of Pharmacology, Physiology and Neuroscience, University of South Carolina, Columbia, SC, United States.
authors.forename: Isiasha
authors.initials: I
authors.lastname: Mark
authors.affiliation: Department of Pharmacology, Physiology and Neuroscience, University of South Carolina, Columbia, SC, United States; Department of Pharmaceutical and Administrative Sciences, Presbyterian College School of Pharmacy, Clinton, SC, United States.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Sweitzer
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002211:Capsaicin / Q000494:pharmacology*; D019332:Endothelin-1 / Q000494:pharmacology*; D005260:Female; D007839:Functional Laterality; D006930:Hyperalgesia / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D017288:Pain Threshold; D010812:Physical Stimulation; D020671:Posterior Horn Cells / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D017207:Rats, Sprague-Dawley; D012737:Sex Factors; D014110:Touch
chemical_list: D019332:Endothelin-1; D016760:Proto-Oncogene Proteins c-fos; D002211:Capsaicin
keywords: Capsaicin; Endothelin-1 (ET-1); Neonatal rat; Nociception