Effects of neonatal monosodium glutamate treatment on substance P binding sites in the rat retina.
We have demonstrated a high affinity specific binding of 125I-Bolton Hunter conjugate of substance P (125I-BHSP) to rat retina membranes. The binding was saturable and monophasic with a Kd of 0.2 nM and a Bmax of 290 fmol/mg protein. The rank order of potency of tachykinins and related analogues in inhibiting 125I-BHSP binding conformed to that of the NK-1 (identical to SP-P) tachykinin receptor, with SP greater than NKA greater than or equal to KAS greater than or equal to NKB and [Glp6, L-Pro9]SP(6-11) being 60 times more active than [Glp6, D-Pro9]SP(6-11). After neonatal monosodium glutamate (MSG) treatment, there was a marked reduction in the number but not binding affinity of 125I-BHSP binding sites in the retina. The same treatment had no effect on either the number or binding affinities of NK-1 sites in the salivary gland.
Lee
C M
CM
Department of Biochemistry, Faculty of Medicine, Chinese University of Hong Kong, Shatin, N.T.
Cheung
W T
WT
D000818:Animals; D000831:Animals, Newborn; D005971:Glutamates / Q000494:pharmacology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter / Q000187:drug effects* / Q000378:metabolism; D012160:Retina / Q000187:drug effects / Q000378:metabolism*; D012970:Sodium Glutamate / Q000494:pharmacology*; D013373:Substance P / Q000378:metabolism*; D013388:Succinimides / Q000378:metabolism*; D015320:Tachykinins / Q000494:pharmacology
C043194:Bolton Hunter reagent-substance P conjugate; D005971:Glutamates; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter; D013388:Succinimides; D015320:Tachykinins; D013373:Substance P; D012970:Sodium Glutamate