Nervous system general account

Pentamidine is not well absorbed from the intestinal tract after oral administration and generally is given by intramuscular injection. The drug binds to tissues, particularly the kidney, and is slowly excreted, mostly as the unmodified drug. It does not enter the central nervous system (CNS). Its sequestration in tissues accounts for its prophylactic use in trypanosomiasis. 

The perception of form can be said to result, in part, from characteristics of the nervous system, as well as learning and experience. Yet there is no single theory of form perception that can fully account for the ability to perceive form. Nor is there a general principle that can pull together the mauy different types of form perception. 

The precise mechanism of toxicity of cyclohexane has not been identified, but is likely similar to other central nervous system (CNS) depressants and general anesthetics. These compounds are believed to exert their effects through a general interaction with the CNS, and interference with neuronal membrane functions has been postulated as a mechanism of action. Disruption of membrane enzymes and the corresponding alterations in cell functions may account for the behavioral and anesthetic effects observed following exposure to various solvents. 

Since completion of this manuscript, a number of reviews have appeared covering various aspects of Parkinsonism such as the use [557], mode of action [558], metabolism [559], and side-effects [560, 561] of L-dopa and the antagonism of its effects by pyridoxine [562], Other useful sources include general accounts of Parkinsonian therapeutics [563-565], the role [558, 566] and distribution [567] of dopamine in the central nervous system, and the pharmacology and biochemistry of 6-hydroxydopamine [567, 568]. Furthermore, there appear to be two forms of Parkinsonism, one more refractory to nicotine than the other [569], and it is significant that nicotine is a known cholinergic tremorogen and produces a Parkinsonian syndrome in animals [8]. 

Seventeenth-century English physiologists did not confine the use of chemistry to the explanation of the vital functions of the human body, they also had recourse to chemistry to account for the physiology of the brain and in general of the nervous system. This becomes paticularly apparent if we consider the notion of animal spirits. The one adopted by the majority of British... 

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