Environmental chemical signals

Zimmer, R. K., Commins, J. E., and Browne, K. A., Regulatory effects of environmental chemical signals on search behavior and foraging success, Ecology, 80, 1432, 1999. 

Ache and coworkers demonstrated that both cyclic nucleotides and inositol phosphates mediate the transduction of environmental chemical signals by the olfactory neurons of P. argus.62 65 Both biochemical and molecular biological techniques have shown that the receptor cells contain various G-protein subunits that would be necessary for signal detection by G-protein-associated chemoreceptors.48 49 66-69 In combination with electrophysiological studies,... 

Monti-Block et al. (1994) [268] found that the adult human VNO is a functional chemosensory organ with a sexually dimorphic specificity to patented chemical stimuli called "vomeropherins" which seem to fit the definition of pheromones. The adult human VNO also appears to have the ability to transduce social-environmental chemical signals, which modulate certain autonomic functions (e.g., electrodermal activity and body temperature). 

Moore P.A., Atema J. and Gerhardt G.A. (1992). The structure of environmental odor signals from turbulent dispersion to movement through boundary layers and mucus. In Chemical Signals in Vertebrates 6 (Doty R.L. and Muller-Schwarze D., eds). Plenum, New York, pp. 79-83. 

Regier F. and Goodwin M. (1977). On the chemical and environmental modulation of pheromone release from vertebrate scent marks. In Chemical Signals in Vertebrates 1 (Muller-Schwarze D. and Mozell M.M., eds.), pp. 115-134. 

The use of a species chemical ecology to control pest animals allows an environmentally sensitive control method. Chemical signals within a species are usually... 

Finally, there are ion channels that respond to intracellular (as opposed to extracellular or environmental) chemical stimuli. These form part of cellular signaling pathways and may be opened by cellular messengers such as calcium ion, Ca +. Such channels are known as signal-gated ion channels. 

FIGURE 8.4 The Bronson model of priming pheromone actions in rodents. Chemical signaling between males and females constitutes a feedback mechanism that results in accelerated maturation and reproduction. This, in turn, permits the mice to adjust their reproduction and population size quickly to respond to environmental conditions such as sudden food abundance at harvest time. FSH, follicle-stimulating hormone LH, luteinizing hormone PRL, prolactin. Stimulation and inhibition are marked by - - and —, respectively. (From Bronson and Coquelin, 1980.)... 

The hippocampus has innumerable afferent and efferent connections to other brain structures both within the limbic system and beyond. There are receptors for many different chemical signals ranging from the "classical neurotransmitters such as acetylcholine to steroid hormones and neurotrophic factors. Some of these receptors are located in the synapses that form the intrinsic hippocampal circuits and others are the targets of specific projection pathways from other brain areas. A comprehensive review of all neurotransmitter interactions relevant to function is not within the scope of this chapter. There are detailed reviews of modulation of neurochemical systems on place learning in the watermaze (McNamara and Skelton, 1993) or other limbic-system dependent tasks (Izquierdo and Medina, 1995) in animals. The effects of key neurochemical, other than NMDA channel-mediated, and environmental influences are discussed below. 

SW Burchiel University of New Mexico Albuquerque, Albuquerque, NM Examine the influence of environmental chemicals on human breast epithelial cell growth and signaling associated with endogenous growth-factor receptors ... 

The organismal division of labor that resulted from the development of multicellularity brought about behavioral repertoires that, by the standards of single-celled life forms, can be considered complex. The study of the organismal, cellular, and molecular ways in which environmentally encountered chemical signals influence behaviors associated with feeding, development, and social interactions has made important contributions to our understanding of chemoreception. 

The reaction of mammals to olfactory stimuli is certainly much more influenced by experience, environmental factors and other sensory inputs than is the reaction of insects to pheromones. Moreover, the same odour may serve different behavioural functions and these may be dependent on such variables as season, age, etc.. Even the word "pheromone" for chemical signals in mammals has been questioned (2). Although the objections were rebutted (3) the term is today still a matter of controversy or at least discussion (4). 

Other environmental cues, such as water shortage, cause plants to transmit chemical signals to the guard cells, causing them to release potassium, which increases their osmotic potential, and to lose water by osmosis. This causes the guard cells to shrink, so closing the stomata, and decreasing the rate of water transpiration... 

The cell culture analog (CCA) system is one approach attempting to narrow this gap. It is developed to address the issues of reactive metabolite formation and tissue-tissue interaction through exchange of metabolites or signal molecules, and to evaluate potential efficacy and toxicity of pharmaceuticals and environmental chemicals. A CCA device can be considered as a simplified and minimized human/animal body, in which mammalian cell cultures are used to represent key functions of specific organs, and cell culture medium is used as a blood surrogate. 

Wilson has estimated that both drugs and environmental chemical exposures only account for 2-3% of developmental defects in man (Wilson, 1972).Thus, a product-label reference of such an occurrence will be undeserved at least 97% of the time, but also may be the first signal of a teratogenic risk. It may now be appreciated why this 2-3% risk is termed the phantom fetus and also why the difficulty in disproving liability... 

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