Brain, neurotransmitters and

M. Mirmiran and D.F. Svaab, Influence of drugs on brain neurotransmitters and behavioral states during development, Develop. Pharmacol. Therapeutics, (1987), (in press.). 

Newsholme, E.A., Acworth, I.N., and Blomstrand, E., Amino acids, brain neurotransmitters and a functional link between muscle and brain that is important in sustained exercise, in Advances in Myochemistry, Benzi, G., Ed., John Libby Eurotext, London, 1987, pp. 127-138. 

The principal hormones of the human posterior pituitary include the two nonapeptides, oxytocin [50-56-6] and arginine vasopressin [11000-17-2] (antidiuretic hormone, ADH). Many other hormones, including opioid peptides (see Opioids, endogenous), cholecystokinin [9011-97-6] (CCK) (see Hormones, BRAIN oligopeptides), and gastrointestinal peptides, also have been located in mammalian neurohypophysis (6), but are usually found in much lower concentrations (7). Studies have demonstrated that oxytocin and vasopressin are synthesized in other human organs, both centrally and peripherally, and there is considerable evidence for their role as neurotransmitters (see Neuroregulators) (8). 

Other studies indicate that sucrose does not cause hyperactivity. Carbohydrate ingestion increases levels of serotonin (5-hydroxytryptamine), a brain neurotransmitter that promotes relaxation and sleep. Dietary sucrose should theoretically have a calming effect and reduce activity, manifestations which have been observed in case studies (63). To date, clinical investigations have failed to show a significant connection between sucrose consumption and aggressive or dismptive behavior (66). 

Due to their physicochemical properties trace amines can pass the cell membrane to a limited extent by passive diffusion, with the more lipophilic PEA and TRP crossing membranes more readily than the more polar amines TYR. and OCT. In spite of these features, trace amines show a heterogeneous tissue distribution in the vertebrate brain, and for TYR. and OCT storage in synaptic vesicles as well as activity-dependent release have been demonstrated. So far, trace amines have always been found co-localized with monoamine neurotransmitters, and there is no evidence for neurons or synapses exclusively containing trace amines. 

The pharmacodynamic effects of ethanol are complex, and any attempt to link its actions to specific neurotransmitters or isolated brain regions is simplistic. A complicated neural network involved in the actions of ethanol accounts for its reinforcing, intoxicating, and abstinence effects. At the present time, use of medications that target neurotransmitters and neuromodulators affected by ethanol represents a reasonable strategy for the development of pharmacotherapies that reduce the reinforcing effects of alcohol and the craving and withdrawal symptoms that commonly occur in the context of alcohol dependence. 

This book is about neurotransmitters, the substances released from neurons to act on neurons. It covers what they do, how they do it and how their activity is involved in brain function and affected by drugs and disease. 

We have no such pretensions in this book but we do hope to help you to understand how neurotransmitters may be involved in brain function and more particularly how their activity is modified by disease and drugs. As the above quotation implies, this will mean considering the synaptic characteristics of each neurotransmitter, but before we do so, it is important to consider some more general and basic aspects of neurotransmitter function. Thus ... 

Obviously, regulation of food intake depends on many neurotransmitters and hormones but this final section will outline the role played by central 5-HT transmission in this process. It had been the belief for some time that increased 5-HT transmission in the brain reduces food intake (Blundell 1977) and this certainly explains the satiety in rats that follows infusion of 5-HT into the paraventricular nucleus (PVN) of the hypothalamus. However, recent studies using microdialysis have found that 5-HT efflux in the lateral hypothalamus is itself increased by food intake, suggesting the existence of a feedback control system. In fact, because the increase in 5-HT efflux is greater in genetically obese rats than in their lean counterparts, it has been proposed that there is a deficiency in the 5-HT inhibition of food intake in obesity. 

Smith, J.E. Co, C. Freeman, M.E. and Lane, J.D. Brain neurotransmitter turnover correlated with morphine-seeking behavior of rats. Pharmacol Biochem Behav 16 509-519, 1982. 

In 30 years, Glu has progressed from a putative neurotransmitter to being recognized as the major excitatory neurotransmitter in the brain. As such, Glu plays a role in countless brain functions, and it is not surprising, therefore,... 

Unlike many chemicals in the brain, neurotransmitters are not homogeneously distributed, but concentrated in certain regions. For example, almost two-thirds of the dopamine in the brain is found in the bilateral nigrostriatal (mesostriatal) tract (pathway), where the neuronal cell bodies are located in the substantia nigra and the axons terminate in the corpus striatum. When over 85% of these dopaminergic neurons are lost, the characteristic motor dysfunction of Parkinson s disease is seen. 

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