Author Description

Human brain made up of billions of neurons; communicate with each other through chemical messengers which are referred to as neuroactive substances. These neuroactive substances include neurotransmitters, neuromodulators, neurohormones and neuromodulators. Some neurotransmitters also act as neuromodulators and neurohormones. It would be cynical if there will ever be general covenant about the meanings of these neuroactive substances including neurotransmitters since the term neurotransmitter has traditionally been used very loosely indeed which includes neurotransmitters, neurohormones, neuromodulators and neuromodulators. Any alterations in functioning of these neuroactive substances can cause diseases. The brain is the ultimate center that regulates all neurological and behavioral aspects of body through neuronal communications mediated via various neurochemicals as discussed above. Thus, neurologic and psychiatric disorders in most cases are result of disturbed neurochemical balance. Besides the multifaceted involvement of billions of neuronal cells, CNS is a complex organization with its diverse number of neurotransmitter systems as compared to autonomic nervous system, in which the parasympathetic system works on "rest and digest" phenomenon and sympathetic system on "fight or flight" phenomenon. There are more than 20 neurotransmitter systems and multiple receptors for each neurotransmitter as discussed in above sections. Any alterations in neurochemical balance are expressed in the form of neurological or psychiatric disorders like epilepsy, Parkinson's disease (PD), Alzheimer's disease, psychosis, depression, etc. Acetylcholine, noradrenaline, dopamine and 5-HT are of utmost importance amongst neurotransmitters for their profound role in pathogenesis of various neurologic and psychiatric disorders in humans. Yet, the involvement of various proteins and peptides such as neurotrophic factors, growth factors, and endogenous chemical compounds cannot b