One of the most important, aspects of animal models is to suggest, hypotheses about the functioning and the involvement of particular neurotransmission systems and/or particular brain areas in psychiatric disorders.42 This model should allow a better understanding
of some of the pathophysiological aspects of neuropsychiatrie disorders in which anhedonia plays an essential role.
Sleep-wake alternation is an essential component of human biological rhythms, and physiological processes accompanying sleep are fundamental to body recovery. As reflected in waking performance, sleep is one of the major determinants of brain Inhibitors,research,lifescience,medical function. Quality of life, productivity, health, and effective education all depend on the quality of normal brain function. However, the economic and social development in our modem society has led, and will lead, to chronic disruption of sleep in a sizeable proportion of the population. The main contributors to these disruptions can be classified as either environmental (noise Inhibitors,research,lifescience,medical and light pollution), economic/societal (shift- work schedule), or pathological (sleep disorders). The detrimental effects of these factors on sleep increase with age and are expected to have an even larger impact in the future, given the aging population and the increased prevalence/incidence of shift work. At the present time, as much as one third Inhibitors,research,lifescience,medical of the adult population
reports difficulty sleeping,1-3 and sleep disturbance is considered as the second most common symptom Inhibitors,research,lifescience,medical of mental, distress.4 Hie widespread use of prescribed hypnotic medication as well as nonprescription
remedies is an indirect reflection of the high frequency of sleep complaints.2, 5 Sleep disorders are often chronic conditions: one study found that over 40% of those reporting sleep KU-55933 problems had had them for more than 5 years.1 Individuals reporting disturbed sleep are more likely to report emotional distress and recurrent health problems.1 A major prospective investigation suggests that these problems are the consequence and not the Inhibitors,research,lifescience,medical cause of sleep difficulties.6 Deviant, sleep pattern has also been identified as a potentially important problem for physical health. Those who report shorter than average sleep duration (“short-sleepers”) as well as those reporting long sleep duration (“long-sleepers”) have been shown to nearly have an increased risk of mortality.7-9 Despite recent inroads into understanding of the sleep-regulatory neural circuit,10-13 current treatments for sleep disorders act via a limited number of pathways. Most hypnotics target GABAergic (GABA, γ-aminobutyric acid) activity globally in the brain. Other commonly used hypnotics that, were not, designed to treat insomnia (sedative antidepressants and antihistamines) have long half-lives and peripheral side effects. Current treatments for hypersomnia typically enhance dopaminergic transmission.