Document Detail

Structure, innervation and response properties of integumentary sensory organs in crocodilians.
MedLine Citation:
PMID:  23136155     Owner:  NLM     Status:  MEDLINE    
Integumentary sensory organs (ISOs) are densely distributed on the jaws of crocodilians and on body scales of members of the families Crocodilidae and Gavialidae. We examined the distribution, anatomy, innervation and response properties of ISOs on the face and body of crocodilians and documented related behaviors for an alligatorid (Alligator mississippiensis) and a crocodylid (Crocodylus niloticus). Each of the ISOs (roughly 4000 in A. mississippiensis and 9000 in C. niloticus) was innervated by networks of afferents supplying multiple different mechanoreceptors. Electrophysiological recordings from the trigeminal ganglion and peripheral nerves were made to isolate single-unit receptive fields and to test possible osmoreceptive and electroreceptive functions. Multiple small (<0.1 mm(2)) receptive fields, often from a single ISO, were recorded from the premaxilla, the rostral dentary, the gingivae and the distal digits. These responded to a median threshold of 0.08 mN. The less densely innervated caudal margins of the jaws had larger receptive fields (>100 mm(2)) and higher thresholds (13.725 mN). Rapidly adapting, slowly adapting type I and slowly adapting type II responses were identified based on neuronal responses. Several rapidly adapting units responded maximally to vibrations at 20-35 Hz, consistent with reports of the ISOs' role in detecting prey-generated water surface ripples. Despite crocodilians' armored bodies, the ISOs imparted a mechanical sensitivity exceeding that of primate fingertips. We conclude that crocodilian ISOs have diverse functions, including detection of water movements, indicating when to bite based on direct contact of pursued prey, and fine tactile discrimination of items held in the jaws.
Duncan B Leitch; Kenneth C Catania
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  The Journal of experimental biology     Volume:  215     ISSN:  1477-9145     ISO Abbreviation:  J. Exp. Biol.     Publication Date:  2012 Dec 
Date Detail:
Created Date:  2012-11-08     Completed Date:  2013-05-03     Revised Date:  2014-08-05    
Medline Journal Info:
Nlm Unique ID:  0243705     Medline TA:  J Exp Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  4217-30     Citation Subset:  IM    
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MeSH Terms
Alligators and Crocodiles / anatomy & histology*,  physiology*
Azo Compounds / chemistry
Carbocyanines / chemistry
Mechanotransduction, Cellular
Microscopy, Confocal
Microscopy, Electron, Scanning
Neurons, Afferent / cytology,  physiology
Peripheral Nerves / cytology,  ultrastructure
Predatory Behavior
Sense Organs / anatomy & histology*,  innervation,  physiology*
Skin / anatomy & histology,  innervation
Skin Physiological Phenomena
Trigeminal Ganglion / cytology,  ultrastructure
Grant Support
Reg. No./Substance:
0/Azo Compounds; 0/Carbocyanines; 40957-95-7/3,3'-dioctadecylindocarbocyanine; 4197-25-5/Sudan Black B

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

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