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Reproduction phase‐related variations in neuropeptide Y immunoreactivity in the olfactory system, forebrain, and pituitary of the female catfish, Clarias batrachus (Linn.)
Author(s) -
Mazumdar Minakshi,
Sakharkar Amul J.,
Singru Praful S.,
Subhedar Nishikant
Publication year - 2007
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.21462
Subject(s) - biology , medicine , endocrinology , forebrain , neuropeptide y receptor , median eminence , olfactory bulb , neuropeptide , olfactory nerve , olfactory system , testosterone (patch) , catfish , hypothalamus , central nervous system , receptor , neuroscience , biochemistry , fishery , fish <actinopterygii>
The aim of this study was to determine whether neuropeptide Y (NPY) immunoreactivity in the cells and fibers in the forebrain and pituitary of Clarias batrachus is linked to the annual reproductive cycle. A steady rise in luteinizing hormone (LH) immunoreactivity was seen in the pituitary through preparatory (February–April) and prespawning (May–June) phases; it was greatly reduced during spawning (July–August; P < 0.001) and partially replenished during postspawning (September–November; P < 0.01) through resting (December–January) phases. Although NPY immunoreactivity in olfactory receptor neurons and olfactory nerve layer in olfactory bulb was gradually augmented during resting through prespawning phases ( P < 0.001), attaining a peak in spawning phase ( P < 0.001), a dramatic decline was encountered during postspawning phase ( P < 0.001). A similar pattern was also observed in NPY‐containing fibers of the medial olfactory tract (MOT) and pituitary. However, a different pattern of NPY immunoreactivity was observed in the neurons of nucleus entopeduncularis (NE) and nucleus preopticus periventricularis (NPP). Whereas these neurons and fibers in the forebrain showed significant augmentation during the resting through prespawning phases ( P < 0.001), the immunoreactivity dramatically declined during spawning ( P < 0.001) and was partially replenished in the postspawning phase. Testosterone injection of juveniles significantly augmented ( P < 0.001) NPY immunoreactivity in NE neurons. We suggest that NPY cells of NE and NPP, and related fiber systems, might be involved in processing of sex steroid‐borne information and regulation of the gonadotropin‐releasing hormone‐LH axis. J. Comp. Neurol. 504:450–469, 2007. © 2007 Wiley‐Liss, Inc.