A. Dicosmo et C. Dicristo, NEUROPEPTIDERGIC CONTROL OF THE OPTIC GLAND OF OCTOPUS-VULGARIS - FMRFAMIDE AND GNRH IMMUNOREACTIVITY, Journal of comparative neurology, 398(1), 1998, pp. 1-12
In cephalopods, the endocrine optic glands on the optic tract control
the maturation of the gonads. The glands are innervated by the optic g
land nerve, which originates in the central nervous system. To explore
the involvement of neuropeptides in the nervous control of the optic
gland of Octopus vulgaris, the presence and distribution of Phe-Met-Ar
g-Phe-NH2 (FMRF-amide)-like and gonadotropin releasing homone (GnRH)-l
ike peptides were examined in the central nervous system and optic gla
nd by immunohistochemistry. For GnRH immunodetection, antibodies again
st four different forms of GnRH were used: cGnRH-I, cGnRH-II, sGnRH, a
nd mGnRH. The optic gland nerve provides direct and indirect signals c
oming from the centres integration of chemical, visual, and olfactive
stimuli to modulate the glandular activity. In these centres, the subp
edunculate area, the olfactory and optic lobes, and FMRF-amide-like an
d GnRH-Like immunoreactivities were detected. The subpedunculate area
seems to be the source of the FMRF-amide-like peptide, whereas the pos
terior olfactory lobule is the source of the GnRH-like peptide. The im
munoreactive fibres for both neuropeptides leave their sources and dir
ectly enter the optic gland nerve. FMRF-amide- and GnRH-immunoreactive
nerve endings are seen on the glandular cells. The evidence of a poss
ible neuropeptidergic control of optic gland activity reinforces the a
nalogies and the functional parallels in the octopus, insect, crustace
an, and vertebrate hormonal systems. J. Comp. Neurol. 398:1-12, 1998.
(C) 1998 Wiley-Liss, Inc.