Document Detail

The action of spike frequency adaptation in the postural motoneurons of hermit crab abdomen during the first phase of reflex activation.
MedLine Citation:
PMID:  15578187     Owner:  NLM     Status:  MEDLINE    
Cuticular strain associated with support of the shell of the hermit crab, Pagurus pollicarus, by its abdomen activates mechanoreceptors that evoke a stereotyped reflex in postural motoneurons. This reflex consists of three phases: a brief high-frequency burst of motoneuron spikes, a pause, and a much longer duration but lower frequency period of spiking. These phases are correlated with a rapid increase in muscle force followed by a slight decline to a level of tone that is greater than that at rest but less than maximal. The present experiments address the mechanisms underlying the transition from the first to second phase of the reflex and their role in force generation. Although centrally generated inhibitory post-synaptic potentials (IPSPS) are present during the pause period of the reflex, intracellular current injection of motoneurons reveals a spike frequency adaptation that rapidly and substantially reduces motoneuron firing frequency and is unchanged in saline that reduces synaptic transmission. The adaptation is voltage sensitive and persists for several hundred milliseconds upon repolarization. Hyperpolarization partially restores the initial response of the motoneuron to depolarizing current. Spike frequency adaptation and synaptic inhibition are important mechanisms in the generation of force that maintains abdominal stiffness at a constant, submaximal level.
Jacob L Krans; William D Chapple
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2004-12-02
Journal Detail:
Title:  Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology     Volume:  191     ISSN:  0340-7594     ISO Abbreviation:  J. Comp. Physiol. A Neuroethol. Sens. Neural. Behav. Physiol.     Publication Date:  2005 Feb 
Date Detail:
Created Date:  2005-02-15     Completed Date:  2005-06-28     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  101141792     Medline TA:  J Comp Physiol A Neuroethol Sens Neural Behav Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  157-74     Citation Subset:  IM    
Department of Physiology and Neurobiology, University of Connecticut, 3107 Horsebarn Hill Rd., Storrs, CT 06269-4156, USA.
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MeSH Terms
Abdominal Muscles / innervation*,  physiology*
Action Potentials / physiology*
Adaptation, Physiological / physiology
Anomura / physiology*
Motor Neurons / physiology*
Muscle Contraction / physiology
Neuronal Plasticity / physiology*
Posture / physiology*
Reflex / physiology*
Stress, Mechanical
Synaptic Transmission / physiology

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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