Mature and developing visual system of Ceratitis capitata (Diptera, Tephritidae): histochemical evidence of nitric oxide synthase in the wild type and the white eye mutant strains.
Nitric oxide (NO) is acknowledged as a messenger molecule in the nervous system. It has a role in the modulation of the chemosensory information and seems implicated also in visual processes and visually guided behaviour of some insects. In the present study, we used two different strains of the medfly Ceratitis capitata (Diptera, Tephritidae), a wild type eye colour and a white eye mutant line, as models to clarify the involvement of NO in the mature and developing visual system. The comparison between the pattern of enzyme histochemical localization of NO synthase (NOS), through NADPH diaphorase (NADPHd) staining, in the optic lobes of the two strains revealed for adults a stronger intensity of reaction in all the neuropiles and the sub-retinic monopolar cell layer of the wild type flies, with respect to the white eye mutant correspondent areas. Anti-NOS immunocytochemistry correlated with these results, underlying reactivity both in fine fibres and varicosities and in cell bodies and supporting the idea of presence of NOS also in the retina of the medfly optic lobes. NADPHd reactivity was present in the first developmental stages of the white eye mutant also, but at lower intensity than wild type, and it decreased in some areas during the transition to adult fly stage both in the wild type and in the white eye mutant. All these observations together indicate that changes in the NO system of C. capitata could be related to the visual information processing, when the visual response or discrimination are altered. Furthermore, NO may be involved in the establishment of the retinal projection pattern and in the control of optic lobes morphogenesis.
Conforti
E
E
Dipartimento di Biologia Animale, Lab. Istologia, Centro di Studio per l'Istochimica del C.N.R., Università degli Studi di Pavia, Piazza Botta 10, 27100, Pavia, Italy.
Torti
C
C
Malacrida
A R
AR
Bernocchi
G
G
D000818:Animals; D008058:Dihydrolipoamide Dehydrogenase / Q000032:analysis; D004175:Diptera / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D009154:Mutation; D019001:Nitric Oxide Synthase / Q000032:analysis*; D009899:Optic Lobe, Nonmammalian / Q000166:cytology / Q000201:enzymology / Q000502:physiology; D014785:Vision, Ocular; D014795:Visual Pathways / Q000166:cytology / Q000201:enzymology / Q000502:physiology*; D014796:Visual Perception
D019001:Nitric Oxide Synthase; D008058:Dihydrolipoamide Dehydrogenase