PubMed HealthSearch

Biomedical subjects

B F Petrie

Publications and source records attributed to B F Petrie.

6 recordsLinked to original sources

Environment is not the most important variable in determining oral morphine consumption in Wistar rats.

The role of differential housing on sucrose-morphine consumption in outbred Wistar rats was investigated in two studies. The results of earlier research, indicating rats housed in a quasinatural colony drank significantly less sucrose-morphine than rats isolated in standard laboratory cages, could not be replicated, as the consumption of sucrose-morphine by the isolated animals in the present two studies was reduced. It is possible that during a colony conversion the supplier inadvertently introduced strain differences making the present rats more resistant to xenobiotic consumption. Discussion documents the role of genetics in morphine consumption.

Animals

Learning set spatial navigation performance in three mouse strains.

Swiss Webster (SW), Dilute Brown Agouti (DBA), and Deer Mice (DM) were tested for acquisition and retention of a learning set place task in the Morris water maze. The learning set consisted of daily placing the hidden platform sequentially at 1 of 4 separate locations in the pool. All animals swam for 63 days in this version of the water task. SW animals were unable to find the platform reliably. The time taken by DBA and DM animals in escaping the pool declined rapidly, reaching asymptote within 21 days. The DM animals reached the platform significantly faster than either SW or DBA mice. Analyses of swim path selection used by the 3 strains indicated clearly that DM mice were the most systematic in the selecting and sequencing from a variety of potential strategies the appropriate methods necessary for the most efficient solution of the problem. The present results suggest that in light of the differences between strains observed in swimming behaviors, investigation of strain differences in the neuroanatomic structures believed to be related to the solving of spatial problems might be useful.

Animals

Parenteral domoic acid impairs spatial learning in mice.

The present study is the first to examine the effect of a single intraperitoneal injection of the neuroexcitotoxin domoic acid on learning in mice. Compared to saline controls, animals exposed to domoic acid (2.0 mg/kg) showed significant impairment on the acquisition of the place task in the Morris water maze. Observation of swim paths taken by mice searching for the underwater platform revealed a failure on the part of the domoic acid-exposed mice to select the appropriate problem solving strategies. The results, along with neuroanatomic work done here and elsewhere, suggest that impairment of acquisition and retention of this spatial navigation task by domoic acid, involves a neuropathology that includes not only the hippocampus, but other limbic, and possibly extralimbic brain regions.

Animals

Cholinergic blockade in the rat impairs strategy selection but not learning and retention of nonspatial visual discrimination problems in a swimming pool.

A procedure was developed to study black versus white and horizontal versus vertical pattern visual discriminations in a swimming pool. The effects of central cholinergic muscarinic receptor blockade by atropine sulfate was then evaluated. The drug treatment impaired acquisition but not retention. Behavioral observations showed that the control rats used a number of strategies during the process of problem solving that facilitated acquisition of the discrimination. Through modifications of training procedures, the processes of strategy selection and discrimination learning were dissociated. Cholinergic blockade was found to impair strategy selection but not discrimination learning. The results question the widely held view that cholinergic systems are involved in learning and memory and suggest instead that cholinergic systems are involved in the selection of the movements or strategies that are prerequisite for learning.

Animals

Naltrexone does not increase brain and body development in rats.

Two strains of preweanling rats (88 Long-Evans; 120 Sprague-Dawley) were given daily SC injections of either 50 mg/kg naltrexone or the equivalent volume of saline, from birth to postnatal day 21. Brain and body weights were assessed at the end of the injections, and in Long-Evans animals, significant differences were noted on both measures with the outcome favoring the control animals. No significant differences were observed between the naltrexone and control Sprague-Dawley rats. These results disconfirm the hypothesis that increased postnatal growth is accomplished by prolonged early postnatal opioid receptor blockade.

Animals