Brain neurotransmitter systems

The neurochemistry of schizophrenia has been considered in a variety of ways by numerous investigators and most have, as here, focussed on the role of abnormalities and/or dysfunction of brain neurotransmitter systems in the disease. Implicit in a book on the neurochemistry of consciousness is the assumption that this chapter will address the neurochemical basis of the disturbance (s) of consciousness that occurs in schizophrenia. Consciousness in its particular and generally-understood meaning is not obviously distorted in schizophrenia, although schizophrenic patients clearly have a different, or abnormal experience of the external world—their conscious awareness is disturbed. 

Maggi A, Enna SJ Regional alterations in rat brain neurotransmitter systems following chronic lithium treatment. J Neurochem 34 888-892, 1980 Maggi A, Perez J Minireview role of female gonadal hormones in the CNS clinical and experimental aspects, life Sci 37 893-906, 1985 Maitre L, Baltzer V, Mondadori C Psychopharmacological and behavioural effects of anti-epileptic drugs in animals, in Anticonvulsants in Affective Disorders. Edited by Emrich HM, Okuma T, Muller AA. Amsterdam, Excerpta Medica, 1984, pp 3-13... 

Manipulating Brain Neurotransmitter Systems to Treat Alcoholism... 

Govoni, S., Memo, M., Lucchi, L., Spano, P. F. and Trabucchi, M. (1980). Brain neurotransmitter systems and chronic lead intoxication. Pharmacol. Res. Commun., 12, 447... 

A medication that causes induction of sleep. The majority of currently available hypnotics (for example benzodiazepine receptor agonists) act via potentiating the brain s inhibitory GABAergic systems, in turn reducing the activity of arousal (i.e. wake promoting) neurotransmitter systems. 

In 1954, experiments by Olds and Milner revealed that the brain has specialized centers for reward functions. In these studies electrical stimulation of certain brain sites was found to be highly rewarding in the sense that rats operantly respond for electrical stimulation of these brain sites, often to the exclusion of any other activity. A neurotransmitter system that is particularly sensitive to electrical self-stimulation is the mesolimbic dopamine projection that originates in the ventral tegmental area and projects to structures closely... 

Lthanol (or alcohol) is a two-carbon molecule that, in contrast to many other drugs of abuse, such as opioids, cocaine, and nicotine, does not bind to specific brain receptors. Nonetheless, alcohol affects a variety of neurotransmitter systems, including virtually all of the major systems that have been associated with psychiatric symptoms (Kranzier 1995). Alcohol affects these neurotransmitter systems indirectly by modifying the composition and functioning of... 

After an overview of neurotransmitter systems and function and a consideration of which substances can be classified as neurotransmitters, section A deals with their release, effects on neuronal excitability and receptor interaction. The synaptic physiology and pharmacology and possible brain function of each neurotransmitter is then covered in some detail (section B). Special attention is given to acetylcholine, glutamate, GABA, noradrenaline, dopamine, 5-hydroxytryptamine and the peptides but the purines, histamine, steroids and nitric oxide are not forgotten and there is a brief overview of appropriate basic pharmacology. 

While brain serotonin systems may play a key role in mediating some of the effects of MDMA on analgesia and body temperature as well as in the reported anxiolytic-like and mood-altering subjective effects of the drug, additional neurotransmitter systems may contribute to some of the unique subjective experiences reported for MDMA and other drugs in this class. 

Histaminergic neurons can regulate and be regulated by other neurotransmitter systems. A number of other transmitter systems can interact with histaminergic neurons (Table 14-1). As mentioned, the H3 receptor is thought to function as an inhibitory heteroreceptor. Thus, activation of brain H3 receptors decreases the release of acetylcholine, dopamine, norepinephrine, serotonin and certain peptides. However, histamine may also increase the activity of some of these systems through H, and/or H2 receptors. Activation of NMDA, p opioid, dopamine D2 and some serotonin receptors can increase the release of neuronal histamine, whereas other transmitter receptors seem to decrease release. Different patterns of interactions may also be found in discrete brain regions. 

Hong JS, Tilson HA, Uphouse LL, et al. 1984. Effects of chlordecone exposure on brain neurotransmitters Possible involvement of the serotonin system in chlordecone-elicited tremor. Toxicol Appl Pharmacol 73 336-344. 

Another problem in validating targets for behavioral disorders related to neurotransmitter abnormalities is the interplay between several neurotransmitter systems in specific brain regions. For example, in the hippocampus, limbic, and nigral-striatal areas, functions connected by serotonin, norepinephrine, and dopamine are interconnected so that blocking selected receptor subtypes or changing synaptic levels of certain neurotransmitters may... 

---