Prenatal stress effects on functional development of the offspring.
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Biomedical subjects
E Fride
Publications and source records attributed to E Fride.
Increased interhemispheric coupling of the dopamine systems induced by prenatal stress.
Maternal noise and light stress, randomly applied throughout pregnancy, has previously been shown to induce alterations in behavioral asymmetries in the adult offspring. In the present study, we investigated whether interhemispheric communication of neurotransmitters would be influenced by this treatment. Dopamine and serotonin turnover rates were measured in the left and right prefrontal cortex, nucleus accumbens and caudate nucleus of adult rats which were stressed prenatally. In control animals, dopamine turnover was only significantly correlated between the left and right hemispheres in the males (p less than 0.01). Prenatal stress greatly increased the degree of interhemispheric correlation (p less than 0.001) which now became highly significant in both sexes (p less than 0.001). For serotonin, left-right turnover rates only correlated in control females and no effect of gestational stress was seen. These results indicate that prenatal stress greatly increases interhemispheric coupling of dopamine in the adult offspring. We suggest that this facilitated communication may underly the alterations in behavioral asymmetries induced by prenatal stress.
3,4-Dihydroxyphenylacetic Acid↗
Effects of prenatal stress on vulnerability to stress in prepubertal and adult rats.
This study investigated the hypotheses that unpredictable prenatal stress has effects on the offspring, similar to those induced by perinatal administration of glucocorticoids and increases the vulnerability to stressful situations at adulthood. Rats were exposed to random noise and light stress throughout pregnancy. Offspring were tested for the development of spontaneous alternation behavior (SA) and at adulthood, their response to novel or aversive situations, open field, extinction and punishment following acquisition of an appetitive response and two-way active avoidance, were assessed. In prenatally stressed rats, the development of SA was significantly delayed. On repeated exposure to an open field they were less active; control rats had elevated plasma corticosterone (CCS) on days 2 and 4 of open field exposure, while prenatally stressed rats had significantly raised plasma CCS after each exposure (days 1-8). Furthermore, punishment-induced suppression of an appetitive response was enhanced. Acquisition of active avoidance was faciliated in female but reduced in male prenatally stressed offspring. It is suggested that random prenatal noise and light stress may cause impairment of development of hippocampal function which lasts into adulthood. This impairment is manifested as an increase in vulnerability and a decrease in habituation to stressful stimuli.
Animals↗
Are the effects of gestational stress on motor development and cerebellar cholinesterase activity mediated prenatally?
Prenatal random noise and light stress retards early motor development in the rat. To determine whether this delay is pre- or postnatally mediated and whether the developing cerebellum may play a role in the delay, rats were subjected to this form of stress and their offspring were fostered or cross-fostered onto control rats and vice versa. Their motor development was assessed by a series of behavioral tests between birth and day 10 of life. Prenatally stressed pups (Eo), whether reared by stressed (Em) or control mothers (Cm), showed a retardation in motor development. However, stressed pups matured earlier when reared by a control mother than by a stressed dam. Control pups (Co) raised by stressed mothers showed normal behavioral development. Cerebellar cholinesterase activity, which has been shown to undergo characteristic alterations with normal maturation, did not differ between stressed and control pups at birth. However, on day 10, cholinesterase activity was lower in EmCo than in CmCo pups, whereas that in CmEo and EmEo pups did not differ significantly from controls. It is concluded that three effects of random noise and light stress during pregnancy may be distinguished: (1) A prenatal effect as expressed by a delay in motor development, (2) a postnatal (rearing) effect on motor development and (3) a rearing effect expressed as a decrease in cerebellar ChE activity.
Animals↗
Prenatal stress impairs maternal behavior in a conflict situation and reduces hippocampal benzodiazepine receptors.
Maternal behavior (pup retrieval) was assessed in prenatally stressed rats during control and conflict situations (having to pass through an airstream) when their pups were 4-5 days old. There was no difference in pup retrieval between experimental and control rats under normal conditions but only 52% of the former retrieved their pups during the conflict situation, compared with 96% of the controls. Catecholamine (CA) levels in the arcuate nucleus (Arc.n.) and noradrenaline in the medial preoptic nucleus (POM) were not altered in prenatally stressed females, but their dopamine levels in the POM tended to be lower (p less than 0.1). The number of benzodiazepine (BZ) receptors in the hippocampi of prenatally stressed females was significantly lower than in controls. We conclude from these results that random prenatal noise and light stress increases the vulnerability to stressful situations in the female offspring during adulthood, which may be accompanied by altered CA function in the hypothalamus and BZ binding in the hippocampus.
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The effects of prenatal exposure to predictable or unpredictable stress on early development in the rat.
Pregnant rats were exposed to different schedules of noise and light stress, and the development of their offspring was studied during the first 2 weeks of life. Motor development was measured by different tests: Righting reflex (Days 2-4); cliff avoidance (Days 4-10); turning on an inclined plane (Days 5-10); and swimming behavior (Days 6-10). Development of motivation-involved behavior was measured with a home-seeking test (Days 6-16). Other developmental landmarks such as acoustic response (Days 12-14) and eye-opening (Days 14-17) were also recorded. Thrice-weekly random stress resulted in a delay in the development of all behaviors studied. Daily stress exposure throughout pregnancy resulted in smaller litters with heavier pups, but otherwise normal behavioral and physical development. Rats exposed to daily stress during the last week of pregnancy only produced litters that did not differ in size and body weight, but that displayed accelerated development of all parameters (except for eye-opening) from Day 6 onwards. It is concluded that the unpredictable nature of prenatal stress is responsible for delays in behavior of offspring.
Animals↗
Endocannabinoids in the central nervous system--an overview.
Many aspects of the physiology and pharmacology of anandamide (arachidonoyl ethanol amide), the first endogenous cannabinoid ligand ("endocannabinoid") isolated from pig brain, have been studied since its discovery in 1992. Ethanol amides from other fatty acids have also been identified as endocannabinoids with similar in vivo and in vitro pharmacological properties. 2-Arachidonoyl glycerol and noladin ether (2-arachidonyl glyceryl ether), isolated in 1995 and 2001, respectively, so far, display pharmacological properties in the central nervous system, similar to those of anandamide. The endocannabinoids are widely distributed in brain, they are synthesized and released upon neuronal stimulation, undergo reuptake and are hydrolyzed intracellularly by fatty acid amide hydrolase (FAAH). For therapeutic purposes, inhibitors of FAAH may provide more specific cannabinoid activities than direct agonists, and several such molecules have already been developed. Pharmacological effects of the endocannabinoids are very similar, yet not identical, to those of the plant-derived and synthetic cannabinoid receptor ligands. In addition to pharmacokinetic explanations, direct or indirect interactions with other receptors have been considered to explain some of these differences, including activities at serotonin and GABA receptors. Binding affinities for other receptors such as the vanilloid receptor, have to be taken into account in order to fully understand endocannabinoid physiology. Moreover, possible interactions with receptors for the lysophosphatidic acids deserve attention in future studies. Endocannabinoids have been implicated in a variety of physiological functions. The areas of central activities include pain reduction, motor regulation, learning/memory, and reward. Finally, the role of the endocannabinoid system in appetite stimulation in the adult organism, and perhaps more importantly, its critical involvement in milk ingestion and survival of the newborn, may not only further our understanding of the physiology of food intake and growth, but may also find therapeutic applications in wasting disease and infant's "failure to thrive".
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