Neurotropic effects of venoms and other factors that promote prey acquisition
| Autor: | Joseph F. Gennaro, Ernest Raymond Casey, Hollis Pace Hall, William K. Hayes |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Sympathetic nervous system
Agkistrodon Physiology Octopodiformes Adaptation Biological Zoology Mollusk Venoms Venom Constriction Epigenesis Genetic Cottonmouth Parasympathetic nervous system Escape Reaction Fish Venoms Parasympathetic Nervous System Genetics Crotalus adamanteus medicine Viperidae Animals Bothrops Nerve Growth Factors Molecular Biology Lung Ecology Evolution Behavior and Systematics biology Crotalus Rana pipiens Ciliary ganglion Pupil Anatomy biology.organism_classification medicine.anatomical_structure Predatory Behavior comic_books Cats Animal Science and Zoology Rabbits comic_books.character Fishes Poisonous Snake Venoms |
| Zdroj: | Journal of experimental zoology. Part A, Ecological genetics and physiology. 307(9) |
| ISSN: | 1932-5223 |
| Popis: | Mammals envenomed by either the Eastern diamondback rattlesnake (Crotalus adamanteus) or the cottonmouth (Agkistrodon piscivorus piscivorus) exhibit an immediate but transitory pupillar contraction, a parasympathomimetic effect mediated through the ciliary ganglion that can be prevented by a retrobulbar injection of anesthetic. The venom of the cottonmouth injected into the lymph spaces of the frog (Rana pipiens) produces an immediate and total collapse of the lung sacs. Applied locally to the surface, it produces a constriction that eventually collapses the entire sac. Tests of venoms and toxins from both anterior and posterior parts of the venom apparatus indicate that the lung-collapsing moiety originates in the accessory, not the main portion of the venom gland. This is the first example of a functional specialization within the whole structure. It seems that this factor is elaborated primarily in snakes that prey upon frogs, although insufficient data are available from this study to confirm this. In both reptile species, the predatory strike is accompanied by an immediate effect, perhaps mediated by the parasympathetic nervous system, designed to incapacitate the prey and facilitate capture. These effects cannot now be attributed to neurotoxins because the effect of the former is transitory (and not lethal) and neither has been purified sufficiently to determine potency or structure. Both take part in securing, but not killing, the prey, and both directly oppose the sympathetic nervous system "fright-fight/flight" response. Evidence is presented to support the possibility that known epigenetic mechanisms are capable of effecting heritable changes in gene expression that could allow for the development of factors that facilitate prey acquisition and promote rapid adaptation to environmental change. |
| Databáze: | OpenAIRE |
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