|
|
||||||||
The Journal of Neurophysiology Vol. 82 No. 4 October 1999, pp. 1759-1767
Copyright ©1999 by the American Physiological Society
Committee on Neurobiology and Department of Neurobiology, Pharmacology, and Physiology, University of Chicago, Chicago, Illinois 60637
Keating, Christopher and
Philip E. Lloyd.
Differential Modulation of Motor Neurons That Innervate the Same
Muscle but Use Different Excitatory Transmitters in
Aplysia. J. Neurophysiol. 82: 1759-1767, 1999. The medial portion of intrinsic buccal muscle 3 (I3m) is
innervated by two excitatory motor neurons, B3 and B9. B3 uses
glutamate as its fast transmitter and expresses the neuropeptide
FMRFamide, whereas B9 uses acetylcholine as its fast
transmitter and expresses the neuropeptide SCP. This preparation was
used to study peptidergic modulation of muscles innervated by neurons
that use different fast excitatory transmitters. First, we determined
the effects of the application of the neuropeptides expressed in these
neurons on excitatory junction potentials (EJPs) and contractions.
FMRFamide increased the amplitude of EJPs and contractions evoked by B3 while decreasing those evoked by B9. This is the first observation in
buccal muscle of a substance that modulates two excitatory neurons
innervating the same muscle in opposite directions. SCP increased EJPs
contraction amplitude, and the rate of muscle relaxation for both motor
neurons. We determined that SCP potently increased cAMP levels in I3m
as it does in other buccal muscles. Stimulation of B9 also caused
increased cAMP levels in I3m providing independent evidence for SCP
release. Finally, stimulation of B9 increased both the contraction
amplitude and relaxation rate of B3-evoked I3m contractions in a manner
similar to that observed using exogenous SCP. By inhibiting B9's
cholinergic transmission with an antagonist, we were able to observe
modulatory effects of B9 in the absence of fast excitatory effects. We
found that the magnitude of the modulation was dependent on the firing
frequency and did occur at frequencies and patterns of firing recorded
previously for B9 during ingestive-like motor programs.
This article has been cited by other articles:
![]() |
Y. Zhurov and V. Brezina Variability of motor neuron spike timing maintains and shapes contractions of the accessory radula closer muscle of Aplysia. J. Neurosci., June 28, 2006; 26(26): 7056 - 7070. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Zhurov and V. Brezina Temperature Compensation of Neuromuscular Modulation in Aplysia J Neurophysiol, November 1, 2005; 94(5): 3259 - 3277. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. GEOFFROY, R. HUTCHESON, and R. CHASE NERVOUS CONTROL OF OVULATION AND EJACULATION IN HELIX ASPERSA J. Mollus. Stud., November 1, 2005; 71(4): 393 - 399. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. Schachtner, B. Trosowski, W. D'Hanis, S. Stubner, and U. Homberg Development and steroid regulation of RFamide immunoreactivity in antennal-lobe neurons of the sphinx moth Manduca sexta J. Exp. Biol., June 15, 2004; 207(14): 2389 - 2400. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. V. Orekhova, V. Alexeeva, P. J. Church, K. R. Weiss, and V. Brezina Multiple Presynaptic and Postsynaptic Sites of Inhibitory Modulation by Myomodulin at ARC Neuromuscular Junctions of Aplysia J Neurophysiol, March 1, 2003; 89(3): 1488 - 1502. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. E. Fox and P. E. Lloyd Mechanisms Involved in Persistent Facilitation of Neuromuscular Synapses in Aplysia J Neurophysiol, April 1, 2002; 87(4): 2018 - 2030. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. J. H. Elliott and A. J. Susswein Comparative neuroethology of feeding control in molluscs J. Exp. Biol., April 1, 2002; 205(7): 877 - 896. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. E. Fox and P. E. Lloyd Evidence That Post-Tetanic Potentiation Is Mediated by Neuropeptide Release in Aplysia J Neurophysiol, December 1, 2001; 86(6): 2845 - 2855. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. E. Fox and P. E. Lloyd Role of cAMP in the Short-Term Modulation of a Neuromuscular System in Aplysia J Neurophysiol, March 1, 2000; 83(3): 1567 - 1579. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |