Neurosecretory system of the thoracic ganglion and its relation to testicular maturation of the crab, Potamon koolooense (Rathbun)
Joshi, P.C.; Khanna, S.S.
Zeitschrift für Mikroskopisch-Anatomische Forschung 98(3): 429-442
1984
ISSN/ISBN: 0044-3107 PMID: 6485497 Document Number: 233987
The structure and gonadotropic function of the neurosecretory system of thoracic ganglion (TG) in adult male crab, Potamon koolooense, is examined. Four types of neurosecretory cells, designated as A, B, C and D can be distinguished in the TG. The cell types differ from each other in their cytomorphology, distibution, neurosecretory activity and mode of discharge of secretory material. The A-cells show marked annual cyclic changes of synthesis and release of cytoplasmic material in association with the testicular cycle. The cells become highly active during the periods when spermatogonial proliferation and the meiosis occur in the testes. Injections of the TG extract during period of spermatogenic quiescence induce hypertrophy and hyperactivity of the androgenic glands accompanied by the onset of spermatogenesis and an increase in the gonad index. The testicular tubule and vas deferens also show an increase in their diameters. Evidently, testicular activity, particularly the early stages of spermatogenesis, depends on the neurosecretion of TG, especially on the activity of A-cells. The gonadotropic influence of TG seems to be mediated through the secretion of androgenic glands.