Neural Influence

Although melanocytes are derived developmentally from the neural crest, the neural influence on human skin pigmentation is not clearly understood (752). According to some authors, vitiligo results from an increase in activity of the peripheral nerve endings in the skin (24). Neural influences of pigmentation have also been noticed in lower vertebrates where skin color changes rapidly (702, 194). 

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Braithwaite, A.W., Harris, A.J. (1979). Neural influence on acetylcholine receptor clusters during embryonic development of skeletal muscles. Nature (Land.) 279 549-51. 

These external neural influences on intestinal motility are common targets for prokinetic drugs, but events within the bowel can have important effects on intestinal motility and cause the bowel to be refractory to traditional prokinetic therapy. Release of cytokines from activated inflammatory cells is probably an important feature of ileus in many cases. Ileus secondary to reperfusion injury is an anticipated response in horses with small intestinal obstruction. However, even apparently mild intestinal injury can initiate cellular responses that lead to impaired motility. Mild intestinal insult by gentle surgical manipulation activated adhesion molecules on leukocytes and increased the expression of P-selectin and intercellular adhesion molecule 1 on endothelial cells within the vasculature of the muscularis layer of the intestine (Kalff et al 1999). Surgical manipulation of the rodent small intestine resulted in substantial extravasation of leukocytes into the intestinal muscularis, consisting mainly of polymorphonuclear neutrophils, monocytes and mast cells and lasting for days. This cellular inflammatory response within the intestinal muscularis externa was associated with a marked decrease in jejunal circular muscle activity (Kalff et al 1998). 

I., 1985, Chemosensory and neural influences on photoperiodic responsiveness of laboratory rats. Neuroendocrinology, 40 285. 

This is our hypothetical concept of only partially impaired, incomplete loss of neural influence, especially of molecular neurotrophic factors, some of which are still able to be produced from crippled but alive motor neurons. Our putative "dysinnervation" phenomenon can be conceptualized as having some aspects similar to a persistence of the early stages of ordinary "recent denervation," to which it appears histochemically similar. 

Denervation and dysinnervation abnormalities are usually neurogenous (but, atypically, sometimes can be myogenous see Chapter 1). Conceptually, denervation is a complete loss of neural influence on the muscle fiber (which initially can be reversible by... 

Although many smooth muscles are still rhythmically active when separated from extrinsic innervation, most are quiescent if completely denervated. Net excitatory neural modulation of smooth muscle is the rule. To make things more complex, the influences of innervation to smooth muscle are carried by a rather large number of different transmitters, whose effects are still being investigated. This presumably... 

Of course, while the identification of these distinct systems may be useful there are many neural pathways that would not fit easily into one of them. Thus some inhibitory pathways, such as that from the caudate nucleus to substantia nigra, utilising GABA, are not intrinsic neurons. The dopamine pathway from the substantia nigra to striatum may start from a small nucleus but unlike other monoamine pathways it shows little ramification beyond its influence on the striatum. The object of the above classification is not to fit all neural pathways and mechanisms into a restricted number of functional categories but again to demonstrate that there are different forms of neurotransmission. 

The interactions between the endocrine and neural systems of the GIT are complex, include shared signaling molecules, and can be hard to separate. Therefore, it is likely that the influence(s) of some phytochemicals will cross over between neural and non-neural pathways. Corresponding with this, lumenal administration of capsaicin interacts with visceral neurons to increase GIT motility (Zittel et al., 2001 Topcu et al, 2002) and abrogates the decreased electrolyte and fluid secretion caused by piperine (Capasso et al., 2002). 

W.J. Meissen and L.M.C. Buydens, Aspects of multi-layer feed-forward neural networks influencing the quality of the fit of univariate non-linear relationships. Anal. Proc., 32 (1995) 53-56. 

Pain has always been described as a symptom. However, recent advances in the understanding of neural mechanisms have demonstrated that unrelieved pain may lead to changes in the nervous system known as neural plasticity. Since these changes reflect a process that influences a physiologic response, pain, particularly chronic pain, may be considered a disease unto itself. 

Consistent with these observations, there is some evidence that caffeine may act, in part, on dopaminergic fibers that project into the medial forebrain bundle. Other psychostimulants also appear to act on this system, which may be at least one of the neural mechanisms involved in the development of dependence.271 Further work has suggested a parallel between caffeine and another highly addictive drug, alcohol. Many of the same factors that enter into the development of alcoholism may also influence the development of dependence on caffeine.272... 

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