Elucidating the role of muscarinic receptors in psychosis
Escape latency (A), swimming speed (B), and time spent in the perimeter of the pool (C) did not differ significantly between the two genotypes during either original or reversal learning. (D) Both genotypes spent significantly more time in the training quadrant (black bars) compared with the other quadrants (opposite quadrant, white bars; right quadrant, dark gray bars; left quadrant, light gray bars) in the probe trials conducted after original training.
(E) Also, both genotypes crossed the training site significantly more often than the equivalent sites in the other three quadrants in the probe trials.
The hind paw response was either a foot shake or a paw lick.
In the wire hang test, the mouse was placed on a wire mesh that was then inverted and waved gently, so that the mouse gripped the wire.
(A-E) No significant differences in the conventional hidden platform version of the Morris water maze were detected between genotypes.
All behavioral tests were carried out with male mice (Table . The hot plate test was used to evaluate sensitivity to a painful stimulus.
Mice were placed on a 55.0°C (± 0.3°C) hot plate (Columbus Instruments, Columbus, OH), and latency to the first hind paw response was recorded.
No significant differences were observed between genotypes in vertical activity (B) or margin time (C).
(D) MR KO mice traveled significantly longer than wild-type mice in the dark box but not in the light box.
These abnormal behaviors in mice are thought to be correlates of the symptoms of schizophrenia, including locomotor hyperactivity, abnormal social behavior, and sensorimotor gating deficits [R KO mice traveled longer distances than wild-type mice in the dark box, while no significant differences between genotypes were detected in distance traveled, time spent in the light box, the number of transitions between the light and dark sides, or latency to enter the light box.