Neurochemical fluctuation

Fluctuations in the level of attention or conscious awareness are of particular interest in terms of neurochemical correlates, which may in turn help to identify mechanisms involved in maintaining normal levels of consciousness. There is little direct evidence so far concerning which particular neurochemical parameter might be implicated. However, examination of the pathophysiology of DLB suggests potential mechanisms controlling the level of consciousness. 

A counterpart of evidence that CCK agonists are anxiogenic is to answer the question of whether the CCK system is functionally implicated in non-provoked symptoms of panic or anxiety. It is conceivable that endogenous variations of central and/or peripheral CCK activity may be a neurochemical concomitant of anxiety. It is interesting to mention that serum concentrations of gastrin, a CCK-B agonist, fluctuate in correlation with self-reported tension, conflict, and anxiety in psychiatrically healthy men (M. Feldman et al. 1992). Plasma CCK levels were markedly elevated in sportsmen before a competitive marathon run, as compared with CCK levels under control conditions (Phillip et al. 1992). Plasma concentrations of adrenocorticotropic hormone (ACTH), cortisol, and noradrenaline were also elevated and increased extensively after the running performance. However, CCK levels re-... 

Hu, Y., Wilson, G. S. A temporary local energy pool coupled to neuronal activity fluctuations of extracellular lactate levels in rat brain monitored with rapid-response enzyme-based sensor. /. Neurochem. 1997, 69 1484-1490. 

Cattabem F., Maggi A, Monduzzi M, De Angelis L, and Racagm G (1978) GABA circadian fluctuations in rat hypothalamus / Neurochem, 31, 565-567. 

The examples to be presented illustrate the diversity of fields of applications, but they are mentioned in outline form only. Many biological phenomena used to be modelled by real or formal kinetic models. A biochemical control theory that is partially based on non-mass-action-type enzyme kinetics seems to be under elaboration, and certain aspects will be illustrated. A few specific models of fluctuation and oscillation phenomena in neurochemical systems will be presented. The formal structure of population dynamics is quite similar to that of chemical kinetics, and models referring to different hierarchical levels from elementary genetics to ecology are well-known examples. Polymerisation, cluster formation and recombination kinetics from the physical literature will be mentioned briefly. Another question to be discussed is how electric-circuit-like elements can be constructed in terms of chemical kinetics. Finally, kinetic theories of selection will be mentioned. 

In addition to the direct utility of mathematical models in the analysis of complex chemical systems a unified conceptual framework is offered to the mathematical treatment of problems of chemical kinetics and related areas in biomathematics. Biochemical control processes, oscillation and fluctuation phenomena in neurochemical systems, coexistence and extinction in populations, prebiological evolution and certain ecological problems of Lake j Balaton can be treated in terms of this framework. Though the main body of/ the book deals with spatially homogeneous systems, spatial structures in chemical systems, pattern formation and morphogenesis related to reaction-diffusion models are also mentioned briefly. 

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