Autoradiographic analysis of binding sites for 125I-Bolton-Hunter-substance P in the human eye.
Substance P is known to exert potent effects in peripheral tissues, and is thought to be important for ocular function. The mechanism of action of substance P in the human eye is not known. As a basis for biochemical characterization specific binding of 125I-Bolton-Hunter-substance P was demonstrated in the human eye using autoradiographic methods. Biochemical characterization on slide-mounted tissue preparations showed that binding was saturable with a KD of 0.27 +/- 0.1 nmol/l. Specific binding occurred at comparable autoradiographic densities to both human retina and choroid. Substance P and its carboxyterminal fragment, substance P(3-11), were shown to be highly potent in binding competition experiments against 125I-Bolton-Hunter-substance P. Similar concentrations of substance P(1-9), neurokinin A and neurokinin B failed to significantly alter specific binding of 125I-Bolton-Hunter-substance P. The results indicate expression of high affinity substance P binding sites in human retina and choroid.
Department of Ophthalmology, University of Innsbruck Medical School, Austria.
G F
GF
Kieselbach
R
R
Ragaut
H G
HG
Knaus
P
P
König
C J
CJ
Wiedermann
D001345:Autoradiography; D001667:Binding, Competitive / Q000502:physiology; D006801:Humans; D007457:Iodine Radioisotopes; D011869:Radioligand Assay; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter / Q000032:analysis*; D012160:Retina / Q000378:metabolism*; D013373:Substance P / Q000378:metabolism*; D013388:Succinimides / Q000378:metabolism*
C043194:Bolton Hunter reagent-substance P conjugate; D007457:Iodine Radioisotopes; D018040:Receptors, Neurokinin-1; D017981:Receptors, Neurotransmitter; D013388:Succinimides; D013373:Substance P