Electrotonic coupling between stratum oriens interneurones in the intact in vitro mouse juvenile hippocampus
Using the isolated juvenile (7â14 days) mouse whole hippocampus preparation, which contains intact complex local circuitry, 145 dual whole cell recordings were made from stratum oriens (s.o.) interneurones under infrared microscopy. In 11.7% of paired recordings, evidence for direct electrotonic c...
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Published in | The Journal of physiology Vol. 558; no. 3; pp. 825 - 839 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
9600 Garsington Road , Oxford , OX4 2DQ , UK
The Physiological Society
01.08.2004
Blackwell Science Ltd Blackwell Science Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Using the isolated juvenile (7â14 days) mouse whole hippocampus preparation, which contains intact complex local circuitry,
145 dual whole cell recordings were made from stratum oriens (s.o.) interneurones under infrared microscopy. In 11.7% of paired
recordings, evidence for direct electrotonic coupling between the s.o. interneurones was obtained from the response of one
interneurone to a long (400â600 ms) constant current pulse passed into the coupled interneurone. When specifically orienting
the dual recordings in the transectional plane of the hippocampus, 18.5% of paired recordings showed electrotonic coupling.
The coupling coefficient, estimated from averaged data, was 6.9 ± 4.7%, ranging from 1.3 to 17.6%. The time constant of the
electrotonically transmitted hyperpolarization was inversely related to the coupling coefficient between the two neurones.
The electrotonic responses of one neurone to constant current pulses injected into the other coupled neurone were intermittent.
Spikes in one of the coupled neurones were associated with small electrotonic EPSPs (spikelets) in the other coupled neurone,
in those neuronal pairs with coupling coefficients greater than 10%. Failure of spikelet production following a spike in the
coupled cell occurred 5â10% of the time. Electrotonic coupling and spikelets persisted in the presence of chemical synaptic
transmission blockade by CNQX, APV and bicuculline, or in zero Ca 2+ perfusate, but were abolished by carbenoxolone (100 μ m ), a gap junctional blocker. These data confirm the existence of electrotonic coupling between s.o. interneurones, presumably
via gap junctions located in dendrites. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Author's present address X.-L. Zhang: Department of Cell Biology and Anatomy, New York Medical, College, Valhalla, NY 10595. |
ISSN: | 0022-3751 1469-7793 |
DOI: | 10.1113/jphysiol.2004.065649 |