Complex, multimodal behavioral profile of the Homer1 knockout mouse.

Proteins of the Homer1 immediate early gene family have been associated with synaptogenesis and synaptic plasticity suggesting broad behavioral consequences of loss of function. This study examined the behavior of male Homer1 knockout (KO) mice compared with wild-type (WT) and heterozygous mice using a battery of 10 behavioral tests probing sensory, motor, social, emotional and learning/memory functions. KO mice showed mild somatic growth retardation, poor motor coordination, enhanced sensory reactivity and learning deficits. Heterozygous mice showed increased aggression in social interactions with conspecifics. The distribution of mGluR5 and N-methyl-D-aspartate receptors (NMDA) receptors appeared to be unaltered in the hippocampus (HIP) of Homer1 KO mice. The results indicate an extensive range of disrupted behaviors that should contribute to the understanding of the Homer1 gene in brain development and behavior.

Lifelong feeding of a high aluminum diet to mice.

In three experiments, high aluminum diets (1000 microg Al/g diet) were fed to mice throughout their life span to determine whether neurodegenerative changes were seen with aging. Brain Al concentrations were slightly lower in Al-treated mice than controls. Generally, no increased mortality or gross evidence of neurodegeneration was seen in Al-treated mice. Eighteen and 24 month old Swiss Webster mice fed the high aluminum diet differed from controls on some neurobehavioral tests, but differences were no greater than previously seen with shorter term exposure in younger mice. Both brain Al concentration and susceptibility to oxidative damage, as measured with TBARS, were lower in the Al-treated aged mice than in controls. In addition, Al-treated aged Swiss Webster and C57BL/6J mice showed somewhat enhanced performance in the Morris water maze. Finally, Al treatment did not exacerbate the effect of MPTP treatment on a grip strength measure in either 66 or 235 day old male mice. Swiss Webster and C57BL/6J mice do not appear to provide useful models for studying Al-induced neurodegenerative changes in aging.

Long-term consequences of developmental exposure to aluminum in a suboptimal diet for growth and behavior of Swiss Webster mice.

Swiss Webster mice received diets containing 7 (control), 100, 500, or 1000 microg aluminum (Al)/g throughout development (conception to 35 days of age) and were tested behaviorally as adults (>90 days of age). The basal diet contained the same percent of recommended dietary amounts of phosphate, calcium, iron, magnesium, and zinc as young women usually consume. These "realistic" dietary conditions led to 12--15% growth retardation in the Al1000 group at the time of testing. Females were evaluated in a cognitive task (Morris water maze) at 3 months of age and males were evaluated in a motor test battery at 5 months of age. Al1000 females (n=16) were slower than controls in learning the Morris maze, as suggested by fewer mice with low latencies during the first three sessions of the four-session learning series. Influences of Al on cue utilization were also found in probe sessions eliminating salient or nonsalient cues. With motor testing, the Al1000 males (n=20) had significantly lower hindlimb grip strength than controls, an effect that was eliminated by covariance analysis with body weight. Subtle influences of Al on rotarod and wire suspension tests were also noted. The data suggest that developmental Al exposure under normal, but less than optimal, dietary conditions can lead to subtle but long-term effects on growth and brain function in adulthood.

Aluminum effects on operant performance and food motivation of mice.

Previous studies demonstrated better performance of operant tasks in mice fed excess aluminum (Al) in the diet. The current study examined whether (a) Al leads to impairment of spatial alternation after extended practice, (b) Al enhances performance of an operant task that emphasizes motor learning and ability (differential reinforcement of high rates, DRH), and (c) Al enhances food motivation as reflected in progressive ratio (PR) performance. Male Swiss Webster mice were fed purified diets containing 7 (control), 500, or 1000 microg Al/g diet. Subgroups were fed excess Al diets during development (conception to 35 days postnatal) or as adults (35 days postnatal through the end of testing). Operant training and testing were conducted at 50 days postnatal. Data indicated that extended training of developmentally exposed mice did not lead to performance deficits, that DRH performance of both developmentally and adult-exposed mice was enhanced, and that food motivation (PR task) was significantly greater in the adult-exposed group with a similar trend in the developmentally exposed group. Aluminum may bias performance of food-motivated tasks by influencing food motivation.

Perinatal bupivacaine and infant behavior in rhesus monkeys.

To assess the effect of perinatal epidural bupivacaine analgesia on infant behavioral development, bupivacaine (1.2 mg/kg) was administered to term-pregnant rhesus monkeys (treated, n = 11, procedural controls, n = 8) and infant behavior was evaluated for 1 year using a test battery including infant neurobehavioral tests, observation of spontaneous behavior, and structured cognitive testing. No adverse effects of bupivacaine were detected for neonatal neurobehavior, early cognitive abilities, or performance of cognitive tasks by older infants. Bupivacaine infants directed more, shorter fixations at visual stimuli during visual novelty preference testing. Observation of behavior maturation patterns showed that the increase in manipulatory activity that normally occurs at 2 months of age was delayed in bupivacaine infants, and the increase in motor disturbance behaviors that normally occurs at 10 months of age was prolonged. These results are interpreted in terms of life-history and brain maturation landmarks that appear at these ages. The data suggest that epidural bupivacaine does not cause neonatal abnormalities or specific cognitive deficits but can alter the normal course of behavioral development.