title: Functional development of neurokinin peptides substance P and neurokinin A in nociception.
abstract: It is unclear how neonates respond to noxious stimuli. This study examined the role of neurokinin peptides in 3- and 21-day-old rat pups using the preprotachykinin-A (PPTA) knockout mouse, lacking neurokinin A and substance P. We assessed pain behaviors of these mice before the neurokinin system is putatively active, 3 days after birth, and after this system is active, 21 days after birth. The lack of these peptides failed to alter behavioral responses to nociceptive stimulation in the 3-day-old mice. The 21-day-old mice lacking these peptides were less responsive to 5 microl 2% formalin and to high intensity thermal and mechanical stimuli. Thus, the neurokinins appear not to be an important mechanism in the processing of nociceptive information in the infant.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D005260:Female; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D015288:Neurokinin A / Q000172:deficiency* / Q000235:genetics; D010147:Pain Measurement / Q000379:methods*; D011498:Protein Precursors / Q000172:deficiency / Q000235:genetics; D018040:Receptors, Neurokinin-1 / Q000172:deficiency / Q000235:genetics; D013373:Substance P / Q000172:deficiency* / Q000235:genetics; D015320:Tachykinins / Q000172:deficiency / Q000235:genetics
chemical_list: D011498:Protein Precursors; D018040:Receptors, Neurokinin-1; D015320:Tachykinins; C044206:preprotachykinin; D013373:Substance P; D015288:Neurokinin A