| dc.description.abstract | Ethanol-Morphine interactions: a
study of the effects of prenatal exposure on the development and
behavior of the rat.
The purpose of the study was to investigate the effects of
ethanol, morphine and ethanol-morphine on the physical and
behavioral development of the rat. Eighteen female and 18 male
animals from Satinder's Heterogeneous Stock (SHS) were paired.
The dams were then exposed to a regimen of either water, or
morphine (0.5 mg/ml), or ethanol (10% v/v), or ethanol
(10%v/v)-morphine (0.5mg/ml) (high), or ethanol (5%
v/v)-morphine (0.25mg/ml) (low), for 21 days during gestation.
The 116 surviving offspring were observed daily until weaning
(day 28 postpartum) for physical, reflex, and sexual
development. Following weaning the same offspring were tested
for preference towards ethanol and morphine, avoidance learning,
reactivity, and hot-plate nociception. There were two instances
of delayed physical development one due to ethanol, and one due
to ethanol-morphine (high) exposure. There were significant
developmental delays due to morphine exposure, and delayed
female sexual development due to ethanol, and ethanol-morphine
(high) exposure. An overall preference for ethanol was observed
regardless of prenatal exposure. This tendency was reversed
following morphine, or ethanol-morphine (high) exposure. The
consumption of either morphine or ethanol on forced and choice
days was dependent on the order of presentation. The postnatal presentation of ethanol and morphine altered food consumption in
an order-related pattern. Differences due to prenatal exposure
were also observed for the One-Way Avoidance response. It is
suggested that the prenatal exposure to ethanol and morphine did
not significantly affect learning, while the combination of both
agents produced a dose-related hyperresponsivity. The
reactivity and the hot-plate testing paradigms were the least
sensitive indicators of ethanol-, and/or morphine-induced
behavioral effects. The lack of differences is attributed to
the limitations of the two testing situations. It is therefore
recommended that reactivity testing be extended, and that the
hot-plate testing be used in conjunction with postnatal
presentation of ethanol or morphine. | |
