[Effect ot thyroliberin on rat brain opiate receptors].
The ability of thyroliberin to interact with opiate receptors of the rat midbrain and hypothalamus has been studied. It was shown by competitive displacement analysis that thyroliberin did not replace labeled opioid peptides in opiate receptor binding sites when added in vitro at concentrations of up to 10(-5) M. The specific binding of opioid peptides was increased by 10-20% in the presence of 10(-7)-10(-6) M thyroliberin. This effect was, probably, due to the rise in the affinity of high-affinity opiate receptors. At the same time the affinity of low-affinity binding sites was decreased. It is suggested that the antagonistic properties of thyroliberin are mediated by the modulation of the binding characteristics of enkephalin-low-affinity opiate receptors.
D000818:Animals; D001921:Brain / Q000187:drug effects*; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000378:metabolism; D016308:Enkephalin, Leucine-2-Alanine; D007031:Hypothalamus / Q000187:drug effects; D008297:Male; D008636:Mesencephalon / Q000187:drug effects; D051381:Rats; D011957:Receptors, Opioid / Q000187:drug effects* / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*
D011957:Receptors, Opioid; D004743:Enkephalin, Leucine; D013973:Thyrotropin-Releasing Hormone; D016308:Enkephalin, Leucine-2-Alanine
Vliianie tiroliberina na opiatnye retseptory golovnogo mozga krys.