Plasticity of the peptidergic mediation of spinal reflex facilitation after peripheral nerve section in the rat.
The effects of the tachykinin antagonist Spantide II (D-Nic-Lys1,3-Pal3,D-Cl2Phe5,Asn6,D-Trp7,9,Nl e11)-substance P (SP) and the vasoactive intestinal peptide (VIP) antagonist (Ac-Tyr1,D-Phe2)-GRF(1-29)-NH2 on the excitability of the spinal nociceptive flexor reflex to intrathecally (i.t.) applied SP and VIP, respectively, as well as the facilitation evoked by activation of cutaneous C-afferent was examined. Both antagonists blocked the effects of the respective neuropeptides in rats with both intact and sectioned sciatic nerves. Spantide II antagonised C-afferent induced reflex facilitation in rats with intact nerves, but the degree of antagonism declined after axotomy. In contrast, the VIP antagonist did not block C-afferent induced facilitation in rats with intact nerves, but did so after axotomy. The results indicate that the role of tachykinins in mediating C-afferent-induced reflex facilitation is taken over by VIP after axotomy.
Wiesenfeld-Hallin
Z
Z
Department of Clinical Neurophysiology, Karolinska Institute, Huddinge University Hospital, Sweden.
Xu
X J
XJ
Håkanson
R
R
Feng
D M
DM
Folkers
K
K
D000818:Animals; D003213:Conditioning, Psychological; D003714:Denervation; D004558:Electric Stimulation; D009473:Neuronal Plasticity; D010455:Peptides / Q000502:physiology*; D010525:Peripheral Nerves / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012018:Reflex / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*; D013373:Substance P / Q000031:analogs & derivatives / Q000494:pharmacology; D013497:Sural Nerve / Q000502:physiology; D014660:Vasoactive Intestinal Peptide / Q000037:antagonists & inhibitors / Q000502:physiology
D010455:Peptides; C065446:spantide II; D013373:Substance P; D014660:Vasoactive Intestinal Peptide