An electrophysiological study of neurons in the horizontal of the
diagonal band of broca.
Easaw, Jacob C., Theodor Petrov, and Jack H. Jhamandas.
Department oMedicine (Neurology) and Division of Neuroscience,
University of Alberta, Edmonton, Alberta, Canada T6G 2B7
APStracts 3:0222C, 1996.
We examined the morphological and electrophysiological properties of
neurons within the horizontal limb of the diagonal band of Broca
(hDBB) and investigated the role of excitatory amino acid-mediated
synaptic transmission in this region. Whole cell patch clamp
recordings were obtained from hDBB neurons in rat forebrain slices.
The hDBB cells examined in this study display a morphological and
electrophysiological profile that is consistent with the type B, non
-cholinergic cell type. Cable analysis reveals that hDBB neurons are
electrotonically compact and may therefore function as efficient
relays for transmission of inputs to other forebrain target sites.
Application of agonists for AMPA, kainate, NMDA, and metabotropic
receptors all evoke inward currents in hDBB neurons. Pharmacological
analysis of synaptic events indicate that evoked excitatory
postsynaptic currents (EPSCs) are either mediated by non-NMDA
receptors alone or a combination of non-NMDA and NMDA receptors. In
some neurons, the metabotropic receptor agonist, trans-ACPD, reduced
EPSC amplitude without altering postsynaptic input conductance, thus,
suggesting a presynaptic locus of action. The electrical and
pharmacological properties described for hDBB neurons may be
physiologically relevant for the effective transmission of excitatory
synaptic inputs to sites that receive projections from the hDBB.
Received 22 March 1996; accepted in final form 26 June 1996.
APS Manuscript Number C165-6.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 25 July 1996