The Role Of Neuropeptides Encoded On The CDCH-1 gene In The Organization Of
Egg Laying Behavior In The Pond Snail, Lymnaea stagnalis.
Petra M. Hermann, Robert P.J. de Lange, Anton W. Pieneman, Andries ter Maat
and Rene F. Jansen..
Graduate School Neurosciences Amsterdam, Research Institute Neurosciences
Vrije Universiteit, Faculty of Biology, De Boelelaan 1087, 1081 HV Amsterdam,
The Netherlands, Tel: +31-20-4447094, Fax:+31-20-4447123, email:
renej@bio.vu.nl.
APStracts 4:205N, 1997.
ABSTRACT
Egg laying in the pond snail Lymnaea stagnalis is triggered by a discharge of
the neuroendocrine Caudodorsal Cells (CDCs). The CDCs expresses three
different Caudorsal Cell Hormone (CDCH) genes. This gene family express in
total 11 different peptides among which is the ovulation hormone. Besides the
CDCs, the CDCH gene family is expressed in other central and peripheral
neurons. In this study we investigated the role the different CDCH-peptides
play in the organization of egg laying behavior. Egg laying behavior is a
sequence of stereotyped movements in which three phases can be distinguished:
Resting, Turning and Oviposition. We have used the excitation of Right Pedal N
(RPeN) motor neurons as a simple analog of shell turning behavior, one of the
elements of egg laying behavior. RPeN motor neurons were inhibited during the
Resting phase of egg laying but were subsequently excited at the onset of and
during the Turning phase. The excitatory effect could be evoked by application
of beta3-CDCP on RPeN motor neurons in the CNS as well as in isolation, but
not by the ovulation hormone, alpha-CDCP or Calfluxin, the other CDCH-1
peptides tested. The ovulation hormone itself caused inhibition of RPeN motor
neurons. Anti-CDCH-1 positive fiber tracts were found close to the cell bodies
and axons of the RPeN motor neurons. Electrical stimulation of a nerve that
contains these fibers resulted in excitation of the RPeN motor neurons. The
effects of injection of CDCH-1 peptides into intact animals correlated well
with the effects of these peptides on RPeN motor neurons. Injection of beta3-
CDCP or alpha-CDCP into intact animals resulted in immediate Turning behavior
in the absence of egg laying itself. The ovulation hormone and Calfluxin had
no immediate effect on the behavior. Furthermore, our data indicate that the
individual CDCH-1 peptides act on different targets.
Received 11 August 1997; accepted in final form 11 August 1997.
APS Manuscript Number J15-7.
Article publication pending J. Neurophysiol.
ISSN 1080-4757 Copyright 1997 The American Physiological Society.
Published in APStracts on 28 August 1997