Neurons neurochemistry

There are several ways in which possible neurotoxic effects might be studied. First, measurement of cerebrospinal fluid concentrations of dopamine or serotonin metabolites would be a straightforward way of assessing neurotoxicity. There are pitfalls in this approach (as outlined by Dr. Ricaurte (this volume), such as the facts that lumbar cerebrospinal fluid might reflect spinal cord neurochemistry more than it reflected brain neurochemistry, and drugs like /r-chloroamphetamine affect serotonin neurons in spinal cord less than they do those in brain (Sanders-Bush... 

An excellent description of the discovery of neurotransmitters is provided by Valenstein (2005). Only the essentials of neurotransmitter metabolism are covered here for more detailed information the reader is directed to textbooks of neurochemistry, e.g. Siegel et al. (1994). For a more advanced coverage of the topics discussed here as well as information on the electrical properties of the neurons involved, the interested reader is directed to Steriade McCarley (2005). 

Narahashi T, Aistrup GL, Marszalec W and Nagata K (1999). Neuronal nicotinic acetylcholine receptors A new target site for ethanol. Neurochemistry International, 35, 131-141. 

While these proposals provide useful and testable hypotheses, they are based on slim evidence from post mortem neurochemistry of schizophrenia. Since the deficits in GABAergic markers may be interpreted as demonstrating neuronal hypofunction rather than cell loss, they could equally be ascribed to a consequence of, rather than a cause of, glutamatergic abnormalities. It would be valuable to identify temporal changes in neurochemistry over the disease course, rather than end-stage information that most post-mortem studies inevitably provide, as well as more information from individuals at risk for schizophrenia. 

This defines the levels within the CNS. The relative isolation between levels is maintained by circular operations which stabilize the structure at each level. For each level there are many entities organized at that level (for example, many neurons) and such entities prefer interaction with other entities at the same level. A chemical reaction, for example, in the retina of the eye is almost always interpreted as a signal about the outside world, not as a signal about neurochemistry. Thus isolation means that operations at any given level are primarily self-referencing (i.e., they take their own states as inputs for further processing). Coupling refers to exceptions to this "self-referential closure. ... 

Yamada M,Tanabe K,Wada K, Shimoke K, Ishikawa Y, IkeuchiT, Koizumi S, Hatanaka H. Differences in survival-promoting effects and intracellular signaling properties of BDNF and IGF-1 in cultured cerebral cortical neurons. Journal of Neurochemistry,2001 78 940-951. 

Westergaard N, Sonnewald U, Peterson SB Schousboe A (1991) Characterization of microcarrier cultures of neurons and astrocytes from cerebral cortex and cerebellum. Neurochemistry Research 16 919-923. 

Dopamine is a neurotransmitter that has long been of interest to both chemists and neuroscientists. For instance, a loss of dopamine-containing neurons or its transmission is related to a number of illnesses and conditions including Parkinson s disease and schizophrenia. It is therefore of interest to perform quantitative and qualitative determination of dopamine in the extracellular fluid in animals in order to gain an understanding of the neurotransmission processes. Such a study will also aid in correlating neurochemistry with behaviour. 

Among the catecholamines, dopamine has long been of interest to both chemists and neuroscientists. It is one of the most important neurotransmitters and is ubiquitous in the mammalian central nervous system[5]. It modulates many aspects of brain circuitry in a major system of the brain including the extra pyramidal and mesolimbic system, as well as the hypothalamic pituitary axis[6]. It also plays a crucial role in the functioning of the central nervous, cardiovascular, renal and hormonal systems[4], A loss of dopamine containing neurons or its transmission is also related to a number of illnesses and conditions including Parkinson s disease, schizophrenia, motivational habit, reward mechanisms and the regulation of motor functions and in the function of the central nervous, hormonal and cardiovascular system[5,18,19]. It is therefore of interest to measure dopamine in the extracellular fluid in animals to order to monitor neurotransmission processes and correlate neurochemistry with behavior[19]. 

To translate this description into the language of neurochemistry, we may say that it is the natural endowment of individuals to give preference to activities according to the efficiency of the enhancer regulation in the population of cortical neurons responsible for the selected performance. The best performing, the talented individuals will be the ones who mobilize when needed the specific enhancer substance at the optimum concentration (see Sect. 3.2.1). 

Cai, Z., McCaslin, P. P. (1992). Selective effects of cyanide (lOOmicroM) on the excitatory amino acid-induced elevation of intracellular calcium levels in neuronal culture. Neurochemistry, 17, 803-808. 

Olfactory Input Regulates Neurochemistry of Specific MOB Neurons.I7I... 

It is by virtue of the fact that the neuronal plasmalemma can separate charges and establish electrochemical potentials that neurons are capable of becoming excited. By excitability is meant the property of the neuron to initiate and propagate an electrical impulse that is at disequilibrium with the electrochemical potential associated with the resting neuron. A key question in neurochemistry to which a definitive answer has proved elusive to date is whether the initiation of an electrical impulse in an excitable cell commences with a biochemical event (such as the hydrolysis of ATP) or a physical event (such as a conformational change in a plasmalemmal protein) or whether the two events are inseparable. The process of initiation occurs within milliseconds, and as a result, an accurate separation of biochemical and biophysical processes has been difficult. 

In Chapter 8, peripheral aspects of the cholinergic system were considered. The basics of the neuron (Fig. 8-1), specifically the cholinergic neuron (Fig. 8-5), the synapse (Fig. 8-2), and depolarization (Fig. 8-3), were also presented. The significance and chemistry of acetylcholine (ACh) was discussed. Chapter 9 continued with the remainder of the peripheral autonomic nerve plan (i.e., the sympathetic, or adrenergic, system). The biosynthesis of the catecholamines DA, NE, and EP were discussed and illustrated (Fig. 9-1), and the metabolism schemes for NE and EP (Fig. 9-3) and DA (Fig. 9-4) were outlined. Much of the early (before 1960) neurochemistry elucidated, and neurotransmitters identified, were central to the functioning of the peripheral nervous system. 

Ahluwalia, J., Yaqoob, M., Urban, L, Bevan, S., and Nagy, I. (2003) Activation of capsaicin-sensitive primary sensory neurons induces anandamide production and release. Journal of Neurochemistry 84 585-591. 

Gammon, C M., Allen, A.C., and Morell, R (1989) Bradykinin stimulates phosphoinositide hydrolysis and mobilization of arachidonic acid in dorsal root ganglion neurons. Journal of Neurochemistry 53 95-101. 

Hansen, H.S., Lauritzen, L., Strand, A.M., Vinggaard, A.M., Frandsen, A., and Schousboe, A. (1997) Characterization of glutamate-induced formation of Al-acylphosphatidylethanolamine and Al-acylethanolamine in cultured neocortical neurons. Journal of Neurochemistry 69 753-761. 

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