Muscarinic M1, M3, Nicotinic,GABAA and GABAB Receptor ...

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Discussion
between excitation and inhibition is essential for functional sensory networks
(Wehr & Zador, 2003). For example, the relative strength and timing of excitatory
and inhibitory inputs shapes the response to sensory stimuli, which is critical for
the organization and tuning of receptive fields (Marino et al., 2001; Higley &
Contreras, 2006). Our study showed that differential expression of GABAA
receptor subunits in the brainstem of hypoglycemic rats plays an important role in
the excitation/inhibition balance. Depressed GABA mediated hyperpolarizations
also contribute to the vulnerability of these neurons during an episode of energy
failure.
Corpus striatum
Striatal neurons receive myriad of synaptic inputs originating from
different sources. Massive afferents from all areas of the cortex and the thalamus
represent the most important source of excitatory amino acids, whereas the
nigrostriatal pathway and intrinsic circuits provide the striatum with dopamine,
acetylcholine, GABA, nitric oxide and adenosine (Calabres et al., 2000). The high
sensitivity of striatal neurones to energy deprivation is expressed as a disruption of
intrinsic membrane properties as well as an alteration of synaptic characteristics of
cells (Xu, 1995).
In the present study, striatum was chosen because it plays an important
role in the motor coordination and has abundant cortical and subcortical
connections which are strongly activated in motor seizures (Kusske, 1979). The
striatum play an important role in the spreading of seizure from cortical areas to
deeper brain structures. Cortical neurons generate synchronous electrical activity
under a variety of physiological and pathological conditions (Bragin et al., 1999;
Grenier et al., 2003). All classes of striatal neurons receive prominent inhibitory
GABAergic inputs. These inhibitory interactions are likely to be essential for
striatal processing. GABA receptors are found at pre or postsynaptic locations in
almost all neuronal elements in the striatum (Fujiyama, et al., 2000; Waldvogel et