Physiological response, human observers

The final part of the overall toxicological process outlined in Figure 6.10 consists of behavioral and physiological responses, which are observable symptoms of poisoning. These are discussed here, primarily in terms of responses seen in humans and other animals. Nonanimal species exhibit other kinds of symptoms from poisoning for example, plants suffer from leaf mottling, pine needle loss, and stunted growth as a result of exposure to some toxicants. 

The physiologic responses from the use of cocaine in humans are euphoria and excitement, making it a habit-forming substance. Such addictive potential has also been observed in rats (Hartman 1978). High doses can produce confusion, hallucinations, delirium, convulsions, hypothermia, and respiratory failure. It is a toxicant to the cardiovascular and central nervous systems. The acute poisoning symptoms, in addition to those stated above, are nausea, vomiting, abdominal pains, and dilation of the pupils. 

Abstract Cadmium is an important poiiutant in the environment, toxic to most organisms and a potential threat to human heaith Crops and other plants take up Cd from the soil or water and may enrich it in their roots and shoots. In this review, we suimnarize natural and anthropogenic reasons for the occurrence of Cd toxicity, and evaluate the observed phytotoxic effects of plants growing in Cd-supplemented sou or nutrient solution. Cd-induced effects include oxidative stress, genotoxicity, inhibition of the photosynthetic apparatus, and inhibition of root metabolism. We explain proposed and possible interactimis between these modes of toxicity. WhUe discussing recent and older studies, we further emphasize the environmental relevance of the experiments and the physiological response of the plant. 

Neurotransmitters and neuropeptides have been implicated in fear and anxiety. Much of our knowledge of the human neural substrates of fear and anxiety is derived from pioneering work using cat and rodent models. As techniques have advanced, our understanding of the anatomy, neurochemistry and physiology of these responses has progressed. In particular, the development of functional imaging techniques has allowed us to confirm that observations made in a number of animal species may also apply to humans. 

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