Functional cytochrome oxidase histochemistry in the honeybee brain

The variations of neural metabolism induced by surgical and chemical treatments were studied in the honeybee brain by the means of cytochrome oxidase (CO) histochemistry. CO staining is considerably reduced in the alpha-lobe by antennal input deprivation. Chemical stimulation (50 mM K(+)) was linked to an increase of CO staining in antennal lobes (AL) and to a decrease in the basal ring of calyces (Cal). Application of the nicotinic ligand imidacloprid (10(-4) M) resulted in increased CO labelling within 30 min in all the structures analysed. Treatment with a lower concentration (10(-8) M) resulted in reduced staining in Cal and central body (CB). We conclude that CO histochemistry can be used to identify the target structures of cholinergic ligands in the honeybee brain.