ScienceAsia 20 (1994): 157-170 |doi: 10.2306/scienceasia1513-1874.1994.20.157

ROLES OF NEUROSECRETORY CELLS ON GROWTH AND REPRODUCTION AND THEIR SEASONAL VARIATION IN ACHATINA FULICA (GASTROPODA: ACHATINIDAE)

JITTIPAN CHAVADEJ,^a MALEEYA KRUATRACHUE,^b VIYADA SEEHABUTR,^a PRAPEE SRETARUGSA,^a E.SUCHART UPATHAM^b AND PRASERT SOBHON^a

ABSTRACT: The injections of Achatina fulica with cerebral ganglion homogenate and with optic tentacle homogenate revealed that both substances had no effeer on body growth of A. fulica. However, the cerebral ganglion homogenate appeared to increase the oocyte production in the ovotestis of snails. Seasonal variation in number and size of neurosecretory cells in the cerebral ganglia of A. fulica was observed. The number of neurosecretory cells in the cerebral ganglia was high during the rainy season (May-October,1993) and low during the dry season (November - April, 1993). The highest number of neurosecretory cells and the largest cell size were observed in May. The number and size of collar cells in the optic tentacles were similar throughout the year.

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a Department of Anatomy, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
b Department of Biology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.

Received November 1, 1994