Nicotinic acetylcholine receptor ligands differently affect cytochrome oxidase in the Honeybee brain.
The objective of this study was to determine if nicotinic receptor antagonists known for their ability to impair memory in the honeybee could induce changes in brain metabolism. We tested the effect of antagonists [hexamethonium, mecamylamine, alpha-bungarotoxin (alpha-BTX)] and agonist (nicotine) brain injections on cytochrome oxidase (CO) histochemistry. Within as little as 30 min following nicotine injection, an increase of the staining was observed in almost all the structures analyzed. The increase was limited to the alpha-lobe after alpha-BTX injection. In contrast, the antagonists hexamethonium and mecamylamine reduced CO staining in this structure that seems to be involved in information retrieval. These results suggest that the decrease of metabolism in the alpha-lobe obtained with hexamethonium and mecamylamine injections could be related to the impairment of retrieval processes previously observed with these drugs.
Armengaud
C
C
Laboratoire de Neurobiologie de l'Insecte, Université de Toulouse III, 118 route de Narbonne, 31062 Cedex, Toulouse, France. carmenga@cict.fr
Aït-Oubah
J
J
Causse
N
N
Gauthier
M
M
D000818:Animals; D001516:Bees / Q000187:drug effects* / Q000378:metabolism; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D002038:Bungarotoxins / Q000494:pharmacology; D003576:Electron Transport Complex IV / Q000187:drug effects* / Q000378:metabolism; D018738:Hexamethonium / Q000494:pharmacology; D008464:Mecamylamine / Q000494:pharmacology; D011939:Mental Recall / Q000187:drug effects / Q000502:physiology; D009538:Nicotine / Q000494:pharmacology; D018722:Nicotinic Agonists / Q000494:pharmacology*; D018733:Nicotinic Antagonists / Q000494:pharmacology*; D011978:Receptors, Nicotinic / Q000187:drug effects* / Q000378:metabolism
D002038:Bungarotoxins; D018722:Nicotinic Agonists; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; D018738:Hexamethonium; D008464:Mecamylamine; D009538:Nicotine; D003576:Electron Transport Complex IV