F. Sayah et al., Allatostatin-like peptide in the brain-retrocerebral complex of the earwigLabidura riparia: cyclic variations related to the reproductive cycle, INVERTEBR R, 34(2-3), 1998, pp. 269-275
A polyclonal antibody raised against allatostatin-3 of Blattella germanica
(BLAST-3) has been used to immunolocalize allatostatin-like peptides in the
brain-retrocerebral complex of Labidura riparia adult females. Strongly st
ained immunoreactive cells are observed in the pars intercerebralis (14 cel
ls) and mainly in the pars lateralis (32 cells). Fibres leading to the corp
us allatum are also stained. In the deutocerebrum, one cell is immunostaine
d at the root of each antennal nerve. In the tritocerebrum two cells in eac
h brain hemisphere are weakly immunostained. During the reproductive cycle,
these cells and their axons show immunoreactivity at previtellogenic, ovul
ation and ovarian arrest periods. During vitellogenesis, immunoreactivity i
s restricted to only four perikarya in the pars intercerebralis.
When young vitellogenic females are injected with 20-hydroxyecdysone (20E),
which inhibits vitellogenesis, full immunoreactivity reappears, suggesting
sensibility of these cells to 20E as is expected for a negative feed-back
loop (Sayah et al., 1995).
These results show that BLAST-3-like material is produced periodically in L
abidura in correlation with low levels of juvenile hormone and the absence
of vitellogenesis. This study contributes to provide information on the deg
ree of homology of allatostatins across various insects.