Differential effects of guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) on the 2-[125I]iodomelatonin binding sites in the chicken bursa of Fabricius and spleen

Neurosci Lett. 1994 May 23;173(1-2):167-71. doi: 10.1016/0304-3940(94)90175-9.

Abstract

Effects of 10 and 50 mumol/l guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) on 2-[125I]iodomelatonin binding in the chicken bursa of Fabricius and spleen were tested. In the chicken bursa of Fabricius, GTP gamma S increased the Kd of 2-[125I]iodomelatonin binding sites without affecting the Bmax value. In contrast, GTP gamma S caused both an increase in Kd and a reduction in Bmax of 2-[125I]iodomelatonin binding sites in the chicken spleen. Our results suggest the existence of subtypes of melatonin receptors with different receptor-G protein-effector complexes in the avian primary and secondary lymphoid systems.

MeSH terms

  • Animals
  • Bursa of Fabricius / drug effects
  • Bursa of Fabricius / metabolism*
  • Chickens
  • Down-Regulation / drug effects
  • Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology*
  • Guanosine Triphosphate / pharmacology
  • In Vitro Techniques
  • Iodine Radioisotopes
  • Kinetics
  • Melatonin / metabolism
  • Membranes / drug effects
  • Membranes / metabolism
  • Receptors, Cell Surface / drug effects
  • Receptors, Cell Surface / metabolism*
  • Receptors, Melatonin
  • Spleen / drug effects
  • Spleen / metabolism*

Substances

  • Iodine Radioisotopes
  • Receptors, Cell Surface
  • Receptors, Melatonin
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • Guanosine Triphosphate
  • Melatonin