Involvement of electrical signalling in theta frequency oscillations generated in the medial septum/diagonal band of Broca in vitro

Garner, H.L., Racca, C., Buhl, E.H., and Henderson, Z. (2003) Involvement of electrical signalling in theta frequency oscillations generated in the medial septum/diagonal band of Broca in vitro. In: Abstracts from Neuroscience 2003. 582.10. From: Neuroscience 2003, 10-14 November 2003, New Orleans, LA, USA.

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Abstract

Theta frequency (4 – 15 Hz) extracellular field activity can be reliably and repeatedly evoked in the medial septum/diagonal band of Broca (MS/DB) in vitro by the application of kainate. We have previously demonstrated a critical role for inhibitory neurotransmission in the maintenance of this activity and presented data that indicates parvalbumin GABAergic neurons are responsible for pacing rhythmic theta activity in the MS/DB. Evidence of functional electrical coupling between GABAergic interneurons has been reported in the hippocampus and neocortex and it has recently become clear that gap junctions may have a significant function in the generation of neuronal population activity. Here we demonstrate that application of the gap-junction uncoupling agent carbenoxolone causes a significant reduction (P< 0.05, Paired T test) in the kainate induced activity recorded at theta frequency (spectral integral in 4-15 Hz range) in the MS/DB slice in vitro.

MS/DB slices were prepared from male Wistar rats (21 days), which were terminally anaesthetised with pentobarbitone sodium (120 mg.kg-1, i.p.). The animals were transcardially perfused with ~ 25ml of modified ACSF and rapidly decapitated. Longitudinal slices (450 µm) were placed in an interface recording chamber and maintained at 32°C. Persistent theta oscillations were induced by bath application of 100 nM kainate. Carbenoxolone was bath applied to stabilized kainate induced activity at a concentration of 100 μM for 60 minutes. At 60 minutes there was a significant reduction in the theta frequency activity recorded (56.6% ± 2.3) and in peak amplitude (n = 6).

These results indicate a pivotal role for electrical signalling in the theta frequency rhythmic activity induced in the MS/DB upon application of kainate.

Item ID: 46462
Item Type: Conference Item (Poster)
Funders: Biotechnology and Biological Sciences Research Council, Medical Research Council, Wellcome Trust
Date Deposited: 23 Nov 2016 01:58
FoR Codes: 11 MEDICAL AND HEALTH SCIENCES > 1109 Neurosciences > 110902 Cellular Nervous System @ 50%
11 MEDICAL AND HEALTH SCIENCES > 1109 Neurosciences > 110903 Central Nervous System @ 50%
SEO Codes: 97 EXPANDING KNOWLEDGE > 970111 Expanding Knowledge in the Medical and Health Sciences @ 100%
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