Demonstration of specific high-affinity binding sites for [3H]5-hydroxytryptamine in the cestode Hymenolepis diminuta.
[3H]5-HT (0.16-8.32 nM) exhibited saturable and specific binding in membrane preparations of Hymenolepis diminuta. The saturation data produced a non-linear Scatchard plot which could be resolved into sites having apparent dissociation constants (Kd) of 0.17 and 8.30 nM for the high-affinity and low-affinity components, respectively. Drug displacement studies, using radioligand concentrations of 0.6 and 6 nM, revealed that the two [3H]5-HT binding components are pharmacologically distinct and do not conform to any known class of 5-HT recognition site. The physiological significance of these putative 5-HT receptors and their potential usefulness for the selection of new antiparasitic agents are discussed.
D000818:Animals; D001667:Binding, Competitive; D006926:Hymenolepis / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000378:metabolism*; D012701:Serotonin / Q000378:metabolism*; D014316:Tritium
D011985:Receptors, Serotonin; D014316:Tritium; D012701:Serotonin