The effect of intrathecal selective agonists of Y-1 and Y-2 neuropeptide Yreceptors on the flexor reflex in normal and axotomized rats

Citation
Is. Xu et al., The effect of intrathecal selective agonists of Y-1 and Y-2 neuropeptide Yreceptors on the flexor reflex in normal and axotomized rats, BRAIN RES, 833(2), 1999, pp. 251-257
Citations number
44
Categorie Soggetti
Neurosciences & Behavoir
Journal title
BRAIN RESEARCH
ISSN journal
00068993 → ACNP
Volume
833
Issue
2
Year of publication
1999
Pages
251 - 257
Database
ISI
SICI code
0006-8993(19990703)833:2<251:TEOISA>2.0.ZU;2-#
Abstract
We have examined the effects of intrathecal (i.t.) administration of [Leu(3 1),Pro(34)]-neuropeptide Y (NPY) or NPY-(13-36), selective agonists of NPY Y-1 or Y-2 receptors, respectively, on the excitability of the flexor refle x in normal rats and after unilateral transection of the sciatic nerve. In rats with intact and sectioned sciatic nerves, i.t. [Leu(31),Pro(34)]-Npy i nduced a similar biphasic effect on the flexor reflex with facilitation at low doses and facilitation followed by depression at high doses. In contras t, i.t. NPY-(13-36) only facilitated the flexor reflex in normal rats, and at high dose it caused ongoing discharges in the electromyogram. NPY-(13-36 ) caused dose-dependent depression of the flexor reflex in rats after sciat ic nerve transection, in addition to its facilitatory effect. Topical appli cation of [Leu(31),Pro(34)]-NPY or NPY-(13-36) caused a moderate and brief reduction in spinal cord blood flow. No difference was noted between the va soconstrictive effect of [Leu(31),Pro(34)]-NPY and NPY-(13-36). It is sugge sted that activation of Y-1 receptors may be primarily responsible for the reflex depressive effect of i.t. neuropeptide Y in rats with intact sciatic nerves, whereas both Y-1 and Y-2 receptors may be involved in mediating th e depressive effect of NPY after axotomy. (C) 1999 Elsevier Science B.V. Al l rights reserved.