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160 The role of glutamic acid receptors in protection against neurological diseases Nerves communicate with each other in the brain by releasing chemicals which move across a synapse the small space between two nerves. The chemical messengers within the synapse are known as neurotransmitters. Glutamic acid or glutamate is one of the twenty naturally occurring amino acids that are linked together in human cells to synthesize proteins for numerous biological processes.Currentlyglutamate is known to be one of the most common neurotransmitters found in the brain and spinal cord. Glutamic acid is used by nerves in the processing of sensations from the outside world e.g. vision hearing taste and smell skin sensations e.g. pain and touch and muscle movements e.g. walking running and skilled move- ments. Glutamic acid plays a major part in memory formation in different parts of the brain. Paradoxically glutamate is also involved in several neuro- logical and psychiatric disorders e.g. brain damage from motor vehicle accidents stroke epilepsy migraine headaches motor neuron disease Parkinsons disease Alzheimers disease schizo- phrenia and substance abuse. These neurological and psychiat- ric disorders are classified as chronic non-communicable diseases a topic that forms part of The UWIs Faculty of Medical Sciences research themes. The question that has intrigued me over the years and formed the basis of my research is How does a chemical that plays such crucial roles in several normal brain functions also be a major culprit in such a wide array of brain diseases Needless to indicate that given the wide range of actions of glutamate in physiological normal and pathological abnormal processes there are several laboratories worldwide that have been study- ing the actions of glutamate from different perspectives. When glutamate is released by a nerve it acts on four main types of proteins known as receptors to effect changes in other nerves. My research work which has been in very close collabo- ration with Trevor Stone of Glasgow University has focused on the actions and interactions between two of the glutamate receptors known as NMDA and AMPA. Whilst the beneficial effects of glutamate are mediated by both AMPA and NMDA separately or acting together the harmful effects of glutamate are mediated mainly via the NMDA receptors. Our research has shown that in the cerebral cortex nerves initiate steps that make them resistant to the effects of contin- ued activation of the NMDA receptor by glutamate. This finding indicates that there are intrinsic mechanisms that can protect nerves against the harmful effects of glutamate. We have recently found that the loss of sensitivity of NMDA receptors is dependent on the composition of the fluid that bathes nerves cells - known as the cerebrospinal fluid. Our current research work is attempting to determine the substances in the cerebro- spinal fluid that increase or decrease the degree of nerve damage. We anticipate that the results will have very useful application in the treatment of the many diseases caused by glutamate and listed above. Our research has also shown that mild stimulation of AMPA receptors by glutamate prevents the effects of subsequent stimulation of NMDA receptorswithout interfering with normal communication between nerves. The results of our work have demonstrated that although glutamate is both a friend and foe to nerves of the brain there are intrinsic brain mechanisms that protect nerves from the harmful effects of glutamate.Understanding these mechanisms is essential to controlling the harmful effects of glutamate without compromising its widespread essential normal functions in the brain and spinal cord. The alternative approach of blocking glutamate receptors has had limited success because such an approach has been accompanied by serious side effects from the simultaneous blocking of normal brain functions. Our research also examines how glutamate receptor activa- tion interacts with other neurotransmitters in the brain e.g. GABA and adenosineto increase its protective actionsand how the location of glutamate receptors on the nerve influences its physiological versus pathological effects. Currently we are examining how extracts of locally available foods e.g. curcu- min and plants e.g. jasmine and neem could protect a person against some of the diseases listed above by affecting the glutamate receptor. Physiological methods of pain relief There are neural networks in the brain especially the Periaque- ductal Grey Area or PAG that produce pain relief when stimu- lated. It is believed that the pain relief resulting from acupunc- ture may be activating this network.Korean Hand Therapy limits acupuncture skin stimulation to points on the hand to promote treatment of various illnesses. Our research has focused on MEDICAL SCIENCES Professor of Human Physiology Head Department of Pre-Clinical Sciences Tel 868 681 633 or 645 2645 ext. 4621 E-mail PROF. JONAS ADDAE