Changes In Motor Coordination Research Articles

Comparison of the antinociceptive and motor effects of intrathecal opioid agonists in the rat

This study compared the antinociceptive and motor effects produced by intrathecal administration of selective μ-, δ-, and κ-opioid receptor agonists in the rat. Changes in nociceptive threshold were measured using the Randall-Selitto paw-withdrawal test and changes in motor coordination were evaluated using the rotarod treadmill test. Each opioid agonist produced statistically significant, dose-dependent increases in mechanical nociceptive thresholds compared to vehicle controls. In the motor coordination studies, DAMGO and DPDPE, but not U50, 488H, produced statistically significant decreases in rotarod performance scores compared to vehicle controls. The results of these studies suggest that motor side-effects produced by opioid agonists need to be considered when interpreting the results of antinociceptive tests that are dependent on a normally functioning motor system.

Activity states and motor activity in an infant capuchin monkey (Cebus apella) from birth through eleven weeks.

Behavioral states and motor activity of an infant capuchin monkey reared by its mother in a social group were studied for 11 weeks after birth. Manipulative activity was infrequent through the first four weeks after birth; what little occurred was mediated by other animals interacting with the infant. The rate of manipulation increased the most between weeks 8 and 9. At the same time, the most frequent targets of manipulation shifted from the infant's own body and the bodies of others to surfaces and inanimate objects in the cage. Large increases in the proportion of time in an Alert/active state and improvement in postural control also occurred at the end of the second month. The data suggest that major organizational changes in motor coordination and the regulation of behavioral state occurred jointly over a short period of time at about 8 weeks of age. In comparison to other species of monkeys, the capuchin infant displayed later development of manipulation, postural control, and independent locomotion, and greater dependence on social contacts for early interaction with its environment. These characteristics are in accord with the greater neurological immaturity of the capuchin infant at birth compared to other monkeys.

The neurotoxic actions of 6-hydroxydopamine infused into the rat substantia nigra

6-Hydroxydopamine (6-OHDA) 10 and 40 μg/24 h infused bilaterally for 4 days into the rat substantia nigra (SN) caused a ‘freezing’ akinetic response which was apparent within 24 h and which persisted throughout the period of infusion. The infusion of 10 or 40 μg/24 h 6-OHDA into the SN failed to cause any change in motor coordination, or induce limb and body rigidity. The infusion of 40 μg/24 h 6-OHDA led to significant reductions in the striatal levels of dopamine, 3,4-dihydroxyphenylacetic acid, homovanillic acid and noradrenaline; no changes were observed following the 4-day infusion of 10 μg 6-OHDA. The consequences of infusing 6-OHDA into the SN are discussed in relation to those induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 1-methyl-4-phenylpyridine (MPP +) where the spectrum of behavioural and biochemical change caused by 6-OHDA is shown not to mimic the actions of either MPTP or MPP +.

The Rotacone: A New Apparatus for Measuring Motor Coordination in Mice

Abstract: The rotacone is a modified rotarod found suitable for the measurement of drug‐induced changes in motor coordination. On this apparatus mice are forced to walk against increasing surface speed until they drop off the cone. As the test is quick the animals are not exhausted, and there is no problem with mice taking “free rides”. Saline‐treated mice showed a constant performance level in 4 immediately successive trials, whereas animals under the influence of drugs, especially chlordiazepoxide, showed an increase in performance in the 4 trials. After chlorpromazine, meprobamate and chlordiazepoxide there is a graded response with a normal distribution of scores. Pentobarbital gave a response of the all or non type.