Nitric oxide synthse in the brain of wild bees

GALVANI GERÓNIMO L.; ROIG-ALSINA ARTURO; LUISSETTEMBRINI BEATRIZ P.

Cordoba, Huerta Grande

Congreso; First Joint Meeting of the Argentine Society for Neurosciences and the Argentine Workshop in Neurosciences; 2009

Nitric oxide (NO) is a established signaling molecule in the insect nervous system. Several experiments in Apis mellifera suggest an important role of this molecule in the processing of olfactory information, as well as in learning and memory formation. To localize the presence of the enzyme producing NO, nitric oxide synthase (NOS), we carried out immunocytochemistry experiments using universal NOS antiserum and NADPH-diaphorase histochemistry was further chosen to study the distribution of NOS in wild bees species belonging to the family Apidae. Members of this family show differences in social structure and food source preference. We dissected female brains from different species: Apis mellifera workers (social, generalist); Melitoma segmentaria  (solitary, specialist); Leiopodus Lacertinus  (solitary, parasitic). The brains were fixed in paraformaldehyde, and serially sectioned with a cryostat and incubated with the appropriate reagents.In A. mellifera, B. atratus and C. trigonoides, the neuropils of the antennal lobe, optic lobe and lateral protocerebrum were labeled. In both A. mellífera and B atratus the peripheral layers of medial and lateral calyces of the mushroom bodies exhibited staining. Instead, in C. trigonoides the vertical lobe, the pedunculus and the basal ring of the calyces were only stained. In B. atratus we observed positive somata in the optic lobe as well as in neighbouring neuropilar areas. D. distinta exhibited no staining at all. In conclusion, differences in the staining pattern of NADPH diaphorase were observed between social and solitary bees. Within social bees, B. atratus, showed ample staining in cell bodies and fibers, while solitary species displayed either a restricted pattern or no labeling at all. The fact that NADPH-diaphorase staining is present in the optic and antennal lobes of social and solitary bees suggests a role for NO in visual and olfactory primary processing centers.