Whalley, B.J. and Constanti, A. (2006) Developmental changes in presynaptic muscarinic modulation of excitatory and inhibitory neurotransmission in rat piriform cortex in vitro: Relevance to epileptiform bursting susceptibility. Neuroscience, 140 (3). pp. 939-956. 10.1016/j.neuroscience.2006.02.046.
Full text not available from this repository.
Suppression of depolarizing postsynaptic potentials and isolated GABA-A receptor-mediated fast inhibitory postsynaptic potentials by the muscarinic acetylcholine receptor agonist, oxotremorine-M (10 microM), was investigated in adult and immature (P14-P30) rat piriform cortical (PC) slices using intracellular recording. Depolarizing postsynaptic potentials evoked by layers II-III stimulation underwent concentration-dependent inhibition in oxotremorine-M that was most likely presynaptic and M2 muscarinic acetylcholine receptor-mediated in immature, but M1-mediated in adult (P40-P80) slices; percentage inhibition was smaller in immature than in adult piriform cortex. In contrast, compared with adults, layer Ia-evoked depolarizing postsynaptic potentials in immature piriform cortex slices in oxotremorine-M, showed a prolonged multiphasic depolarization with superimposed fast transients and spikes, and an increased 'all-or-nothing' character. Isolated N-methyl-d-aspartate receptor-mediated layer Ia depolarizing postsynaptic potentials (although significantly larger in immature slices) were however, unaffected by oxotremorine-M, but blocked by dl-2-amino-5-phosphonovaleric acid. Fast inhibitory postsynaptic potentials evoked by layer Ib or layers II-III-fiber stimulation in immature slices were significantly smaller than in adults, despite similar estimated mean reversal potentials ( approximately -69 and -70 mV respectively). In oxotremorine-M, only layer Ib-fast inhibitory postsynaptic potentials were suppressed; suppression was again most likely presynaptic M2-mediated in immature slices, but M1-mediated in adults. The degree of fast inhibitory postsynaptic potential suppression was however, greater in immature than in adult piriform cortex. Our results demonstrate some important physiological and pharmacological differences between excitatory and inhibitory synaptic systems in adult and immature piriform cortex that could contribute toward the increased susceptibility of this region to muscarinic agonist-induced epileptiform activity in immature brain slices.
|Uncontrolled Keywords:||piriform cortex; oxotremorine-M; presynaptic muscarinic modulation; depolarizing postsynaptic potentials; fast inhibitory postsynaptic potentials; development|
|Departments, units and centres:||Department of Pharmacology > Department of Pharmacology|
|Journal or Publication Title:||Neuroscience|
|Deposited By:||Library Staff|
|Deposited On:||24 Nov 2011 15:35|
|Last Modified:||24 Nov 2011 15:35|
Item downloaded times since 24 Nov 2011 15:35.
View statistics for "Developmental changes in presynaptic muscarinic modulation of excitatory and inhibitory neurotransmission in rat piriform cortex in vitro: Relevance to epileptiform bursting susceptibility"
Repository Staff Only: Item control page
School of Pharmacy Staff Only: Edit a copy to replace this item