Linked Life Data

9651199

Source:http://linkedlifedata.com/resource/pubmed/id/9651199

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
14
pubmed:dateCreated
1998-7-27
pubmed:abstractText
A presynaptic voltage control method has been used to investigate the modulatory effects of serotonin (5-HT) and okadaic acid (OA) on the inhibitory junction of the crayfish opener muscle. Instead of using action potentials, we used 20 msec pulses depolarized to 0 mV to activate transmitter release. This approach allowed us to monitor two separate physiological parameters related to the release process. The first parameter, transmitter release kinetics, is characterized as the delay when inhibitory postsynaptic conductance reaches its half-maximum (IPSG50). The second parameter, the total area of IPSG (IPSGarea), estimates total transmitter output. We have reported previously that the F2 component of synaptic facilitation is associated with a decrease in IPSG50 but without a change in IPSGarea. These results raised the possibility that IPSG50 and IPSGarea could be mediated by separate mechanisms that were modulated independently. To explore this possibility, we investigated the effects of 5-HT (100-200 nM) and OA (2.5 microM) on the two parameters. 5-HT and OA enhanced IPSG neither by changing the sensitivity of postsynaptic receptors, as tested by iontophoretically ejected GABA, nor by elevating resting and action potential-activated presynaptic free calcium, as monitored by fura-2 imaging. 5-HT and OA decreased IPSG50 by 3.0 +/- 1.4 and 3.6 +/- 1.1 msec, respectively, and increased IPSGarea by 50 +/- 21 and 37 +/- 6%, respectively. The ability of F2 facilitation to accelerate release kinetics was reduced in the presence of the modulators, suggesting that the mechanism underlying the accelerated release kinetics was shared by the two modes of synaptic enhancement. This report demonstrates that the acceleration in release kinetics and the increase in total release are two separate mechanisms for enhancing transmitter output and that these two mechanisms can be activated without changes in presynaptic calcium dynamics.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0270-6474
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
18
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5160-9
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1998
pubmed:articleTitle
Neuromodulators enhance transmitter release by two separate mechanisms at the inhibitor of crayfish opener muscle.
pubmed:affiliation
Department of Biology, Boston University, Boston, Massachusetts 02215, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't