ABSTRACT
Latent inhibition (LI) is a decrement in learning performance that results from the nonreinforced pre-exposure of the to-be-conditioned stimulus, in both vertebrates and invertebrates. In vertebrates, LI development involves dopamine and serotonin; in invertebrates there is yet no information. We studied differential olfactory conditioning of the proboscis extension response in the honeybee Apis mellifera, and we compared LI in individuals treated with antagonists of biogenic amines (dopamine, octopamine, and serotonin). An antagonist of octopamine receptors and two antagonists of serotonin receptors showed LI disruption. We thus provide evidence that serotonin would participate in the regulation of LI in honeybees.
Subject(s)
Conditioning, Classical/physiology , Dopamine/metabolism , Extinction, Psychological/physiology , Inhibition, Psychological , Serotonin/metabolism , Analysis of Variance , Animals , Bees/physiology , Conditioning, Classical/drug effects , Dibenzazepines/pharmacology , Dopamine/pharmacology , Dopamine Antagonists/pharmacology , Ethylketocyclazocine/analogs & derivatives , Ethylketocyclazocine/pharmacology , Extinction, Psychological/drug effects , Fluphenazine/pharmacology , Habituation, Psychophysiologic/drug effects , Histamine H1 Antagonists/pharmacology , Imidazoles/pharmacology , Ketanserin/pharmacology , Methysergide/pharmacology , Odorants , Serotonin/pharmacology , Serotonin Antagonists/pharmacology , Smell/drug effects , Smell/physiologyABSTRACT
Reversed chloroquine (RCQ) is a multiple ligand compound active against chloroquine-sensitive and resistant falciparum malaria. It is composed by a 4-aminoquinoline moiety (like that present in chloroquine (CQ)) joined to imipramine (IMP), a modulating agent that also showed intrinsic antiplasmodial activity against Brazilian Plasmodium falciparum isolates resistant to CQ. Molecular modeling and ultraviolet-visible spectroscopy (UV-vis) studies strongly suggest that the interaction between RCQ and heme is predominant through the quinoline moiety in a mechanism of action similar to that observed for CQ.