Behavioral Measures of Neurotoxicity (1990) / Chapter Skim
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On the Identification and Measurement of Chemical Time Bombs: A Behavior Development Perspective
On the Identification and Measurement of Chemical Time Bombs: A Behavior Development Perspective
Pages 191-205
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From page 191... ...
sensitized basic scientists, clinicians, and legislators to the dangers associated with the administration of drugs prenatally and to the health and wellbeing of the developing neonate (Krasnegor, 1986~. Further, evidence is accumulating that not all the damage suffered by the developing fetus exposed to toxicants during gestation results in physical or neurochemical anomalies.
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From page 192... ...
Answers to these queries are contingent to some extent on the questions being posed and the extant knowledge concerning the developmental trajectory of the behaviors in question. These tactical judgments are also based in part upon the availability of experimental paradigms that can be employed with perinates and the behavioral mechanisms believed to be affected by the putative toxicant.
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From page 193... ...
Clearly, studies which employ prospective designs with substances that are suspected of having behaviorally toxic activity must employ animal models. A traditional choice for behavioral toxicity studies has been laboratory rats.
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From page 194... ...
Based upon such knowledge, one might design experimental studies, employing animal models, that can assess dose-response relationships between a substance and putative effects upon behavioral development. The second approach employs animal models to screen substances for behavioral toxicity.
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From page 195... ...
Further, female offspring have lower birth weights at puberty, show lower fertility, and have delayed onset of puberty (Gupta et al., 1980~. Testosterone concentrations in plasma and brain of neonatal males exposed to barbiturates were lowered by prenatally administered barbiturates (Gupta et al., 1982~.
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From page 196... ...
Carried to its extreme, this approach implies measurement of fetal behavior. During the early part of this century, there was considerable scientific interest in prenatal behavioral development.
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From page 197... ...
A little over 15 years later, Spelt (1948) employed similar procedures and claimed success in demonstrating classical conditioning in the human fetus.
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From page 198... ...
In a series of elegant experiments (Smotherman and Robinson, 1987) which included rigorous control procedures, the investigator and his colleagues demonstrated that rat fetuses exposed to a single-trial pairing of a neutral stimulus (mint)
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From page 199... ...
Further, they employ animal models which they believe validly relate to the human condition. Developmentalists and behavioral toxicologists also strive to pose questions that can elucidate the putative behavioral or neurobehavioral mechanisms which may subsume the observed deficits.
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From page 200... ...
Research in the field of eyelid conditioning has much to recommend it conceptually and experimentally as a paradigm for asking questions of relevance to developmental behavioral toxicologists (Gormezano et al., 1983; Harvey and Gormezano, 1986; Solomon and Pendlebury, 1988~. There are three main factors that make the nictitating membrane response (NMR)
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From page 201... ...
This should be conducted in neonatal humans and young rabbits to fill in the knowledge gap on the ontogeny of the response. The availability of such baseline data will provide developmentalists and behavioral toxicologists with the information needed to evaluate behavioral development and the effects of substances over an impressive age span.
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From page 202... ...
1983. Hippocampectomy selectively disrupts discrimination reversal conditioning of the rabbit nictitating membrane response.
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From page 203... ...
1976. Central cholinergic blockade by scopolamine and habituation, classical conditioning, and latent inhibition of the rabbit's nictitating membrane response.
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From page 204... ...
1981. The septohippocampal cholinergic system and classical conditioning of the rabbit's nictitating membrane response.
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From page 205... ...
1983. Repeated systematic aluminum exposure effects on classical conditioning in the rabbit.
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