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

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Discussion
The Y-maze test is a classic model behavioral test, with a strong aversive
component, utilized for evaluating learning and memory in rats and mice (Katz &
Chudler, 1980; Woo et al., 2008). Spatial memory and exploratory activity have
an influence on behavioural tests including Y-maze performance. In this regard,
the number of novel arm entries and time spent was significantly lower in
hypoglycemic rats compared to diabetic and control group. Hypoglycemic rats
showed performance deficit in Y maze which showed impairment in exploratory
activity which is anxiety dependent behaviour. Intensity of derangement in
hypoglycemic groups exacerbated compared to diabetic and control rats. GABAmediated
neurotransmission in the brain regions of the rat regulate anxiety
(Shekhar et al., 1990). Results show the impairment in spatial memory and
exploratory activity in diabetic rats which is adversely influenced by recurrent
hypoglycemia. This is in agreement with other studies which show that
impairment in cognitive function have been observed in diabetic patients and also
in animal models of diabetes (Brands et al., 2007). These impairments have been
characterized mainly by moderate deficits in learning and memory, psychomotor
slowing and reduced mental flexibility (Cukierman et al., 2005; Brands et al.,
2007). The above data complement clinical and animal studies suggesting that
recurrent hypoglycemia leads to persistent behavioral and cognitive impairments
(Gold et al., 1993; Akyol et al., 2003).
There are also reports on the involvement of the cholinergic system
abnormality in the impaired acquisition and/or retention of passive avoidance
learning. Behavioral abnormalities consequent on an impairment of neuronal
glucose metabolism is suggestive of cholinergic dysfunction (Jackson et al.,
2000). Neurobehavioural derangements are reported to be associated with
cholinergic system (Viberg et al., 2008). Increased Y maze deficit in
hypoglycemic group shows the involvement of cholinergic system; muscarinic,
nicotinic receptor subtype functional regulation in mediating behavioural
impairment. Reduced function by CNS cholinergic systems has been found to be