JN Fuel your research with LabChart
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

J Neurophysiol 75: 2268-2279, 1996;
0022-3077/96 $5.00
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Pastor, J.
Right arrow Articles by Belmonte, C.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Pastor, J.
Right arrow Articles by Belmonte, C.

Journal of Neurophysiology, Vol 75, Issue 6 2268-2279, Copyright © 1996 by APS

ARTICLES

Properties of the nociceptive neurons of the leech segmental ganglion

J. Pastor, B. Soria and C. Belmonte
Departmento de Fisiologia, Universidad de Alicante, Spain.

1. The electrical responses of nociceptive (N) lateral and N medial neurons of the leech segmental ganglion to mechanical, chemical, and thermal stimulation of the skin were studied in a superfused ganglion-body wall preparation. 2. Mechanical indentation of the skin > 10 mN evoked in both types of cells a sustained discharge of impulses; afterdischarge was often observed with suprathreshold stimulations. 3. Application to the cutaneous receptive area of 10-100 mM acetic acid or of NaCI crystals and solutions also elicited a firing response in N medial and N lateral cells. In contrast, capsaicin applied to the skin (3.3 x 10(-5) to 3.3 x 10(-2) M) excited N lateral but not N medial neurons. Likewise, impulse discharges were obtained when capsaicin was applied to the cell bodies of N lateral but not of N medial neurons. 4. In both types of N neurons, heating of the skin above 39 degrees C evoked a discharge of impulses whose frequency was roughly proportional to temperature values. 5. Application of repeated suprathreshold heating cycles at 10-min intervals enhanced the impulse frequency of the response (sensitization). Shorter time intervals between heating cycles depressed the response to heat. Sensitization could not be obtained by equivalent soma depolarizations obtained by intracellular current injection. 6. Impulse discharges evoked by irritant agents were also augmented by previous application of noxious heat. 7. N lateral neurons fired in response to low-pH solutions and capsaicin directly applied onto the ganglion. N medial neurons responded inconsistently to acid and were insensitive to capsaicin. Action potentials evoked in N lateral cells by capsaicin had a slow rise, a prominent hump, and a prolonged afterhyperpolarization. 8. It is concluded that N neurons of the leech segmental ganglion respond to different modalities of noxious stimuli applied to their peripheral receptive fields and develop sensitization after repeated noxious stimulation. These properties are typical of mammalian polymodal nociceptors; thus N neurons may be a simple model for analysis of membrane mechanisms associated with polymodality of nociceptive neurons.


This article has been cited by other articles:


Home page
 J. Neurosci.Home page
P. A. Illich and E. T. Walters
Mechanosensory Neurons Innervating Aplysia Siphon Encode Noxious Stimuli and Display Nociceptive Sensitization
J. Neurosci., January 1, 1997; 17(1): 459 - 469.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Visit Other APS Journals Online