PT  - JOURNAL ARTICLE
AU  - Sahley, CL
AU  - Modney, BK
AU  - Boulis, NM
AU  - Muller, KJ
TI  - The S cell: an interneuron essential for sensitization and full dishabituation of leech shortening
AID  - 10.1523/JNEUROSCI.14-11-06715.1994
DP  - 1994 Nov 01
TA  - The Journal of Neuroscience
PG  - 6715--6721
VI  - 14
IP  - 11
4099  - http://www.jneurosci.org/content/14/11/6715.short
4100  - http://www.jneurosci.org/content/14/11/6715.full
SO  - J. Neurosci.1994 Nov 01; 14
AB  - Sensory neurons in the leech excite the S interneuron, which in turn excites motoneurons that shorten the leech, although activity in the S cell reportedly cannot by itself shorten the animal. Experiments were performed in semi-intact leeches using established dishabituation and sensitization protocols. S-cell activity increased during reflexive shortening once the animal was sensitized or dishabituated with a strong shock. S-cell activity otherwise was not associated with shortening. To test the role of the S-cell in dishabituation and sensitization of the shortening reflex, single S cells were ablated in vivo by intracellular injections of pronase. S-cell lesions reduced but did not eliminate dishabituation; however, sensitization was completely disrupted. This was consistent with recent evidence that separate processes contribute to dishabituation and sensitization. Since the S cell in each ganglion is a link in a rapidly conducting chain along the length of the animal, it may be sufficient to break the chain at a single point to eliminate sensitization.