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

upregulation of muscarinic M3 mRNA level during hypoglycemic condition
compared to diabetic. This is concordant with our receptor binding studies.
Immunohistochemistry study using confocal microscope confirmed a similar
expression pattern in localization of muscarinic M1, M3 receptors in the cerebral
cortex of control and experimental rats. Highest levels of muscarinic M1 and M3
receptors are in cerebral cortex (Brann et al., 1988) which shows the importance
of cholinergic neurotransmission in cerebral cortex; which in the present study
showed altered by recurrent hypoglycemia. Muscarinic M3 receptors are
implication in synaptic inhibition. Inhibition of excitatory transmission by M3
receptors has been reported (Sugita et al., 1991; Hsu et al., 1995; Auerbach &
Segal, 1996). Alterations of mAChR were reported in several neurological and
psychiatric diseases. Cholinergic deficits are accompanied by alterations of the
mAChR in various cerebral regions. Previous reports showed that activation of
muscarinic M1 cholinergic receptors produced an increase of glucose utilization
(Hosey, 1992). The functional regulation of muscarinic receptors is a
compensatory mechanism to facilitate insulin secretion and maintenance of
normoglycemia in diabetic rats. Our findings showed cholinergic hypofunction
mediated through muscarinic M1 and M3 receptors in the cerebral cortex which is
suggested to depress the overall function mediated by cerebral cortex. The results
showed the importance of maintaining euglycemia during diabetes treatment with
insulin therapy.
Cerebellum
Cerebellum is a region of the brain that plays an important role in the
integration of sensory perception, memory consolidation, coordination and motor
control. In order to coordinate motor control, there are many neural pathways
linking the cerebellum with the cerebral motor cortex and the spinocerebellar tract
(Roberta & Peter, 2003). There is currently enough anatomical, physiological and
theoretical evidence to support the hypothesis that cerebellum is the region of the
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