The Journal of General Physiology
Track the topics, authors and articles important to you
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
This Article
Right arrow Full Text (PDF, 1478K)
Right arrow Alert me when this article is cited
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JGP
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Obara, S.
Right arrow Articles by Bennett, M. V. L.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Obara, S.
Right arrow Articles by Bennett, M. V. L.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?
The Journal of General Physiology, Vol 60, 534-557, Copyright © 1972 by The Rockefeller University Press

ARTICLE

Mode of Operation of Ampullae of Lorenzini of the Skate, Raja

S. Obara 1 and M. V. L. Bennett 1

1 From the Department of Anatomy, Albert Einstein College of Medicine, and The Rose F. Kennedy Center for Research in Mental Retardation and Human Development, Bronx, New York 10461.

Dr. Obara's present address is the Department of Physiology, Teikyo University, School of Medicine, Itabashi-ku, Tokyo 173, Japan.

Ampullae of Lorenzini are sensitive electroreceptors. Applied potentials affect receptor cells which transmit synaptically to afferent fibers. Cathodal stimuli in the ampullary lumen sometimes evoke all-or-none "receptor spikes," which are negative-going recorded in the lumen, but more frequently they evoke graded damped oscillations. Cathodal stimuli evoke nerve discharge, usually at stimulus strengths subthreshold for obvious receptor oscillations or spikes. Anodal stimuli decrease any ongoing spontaneous nerve activity. Cathodal stimuli evoke long-lasting depolarizations (generator or postsynaptic potentials) in afferent fibers. Superimposed antidromic spikes are reduced in amplitude, suggesting that the postsynaptic potentials are generated similarly to other excitatory postsynaptic potentials. Anodal stimuli evoke hyperpolarizations of nerves in preparations with tonic activity and in occasional silent preparations; presumably tonic release of excitatory transmitter is decreased. These data are explicable as follows: lumenal faces of receptor cells are tonically (but asynchronously) active generating depolarizing responses. Cathodal stimuli increase this activity, thereby leading to increased depolarization of and increased release of transmitter from serosal faces, which are inexcitable. Anodal stimuli act oppositely. Receptor spikes result from synchronized receptor cell activity. Since cathodal stimuli act directly to hyperpolarize serosal faces, strong cathodal stimuli overcome depolarizing effects of lumenal face activity and are inhibitory. Conversely, strong anodal stimuli depolarize serosal faces, thereby causing release of transmitter, and are excitatory. These properties explain several anomalous features of responses of ampullae of Lorenzini.

Submitted on April 5, 1972


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:


Home page
 J. Neurophysiol.Home page
A. B. Neiman and D. F. Russell
Two Distinct Types of Noisy Oscillators in Electroreceptors of Paddlefish
J Neurophysiol, July 1, 2004; 92(1): 492 - 509.
[Abstract] [Full Text] [PDF]


  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents