Characteristics of behavioral abnormalities in alpha1d-adrenoceptors deficient mice.

To investigate the functional role of alpha1d-adrenergic receptor (alpha1d-AR) in the CNS, we have generated mutant mice lacking the alpha1d-AR using a gene targeting approach and examined in detail the effects of alpha1d-AR knockout mice on motor function, sensory function, and learning and memory. alpha1d-AR knockout mice showed better motor coordination at the highest rotating speed of the rotarod performance and stronger muscle tone using the traction meter, but their locomotor activity and swimming ability in the water maze were not affected. In the water maze requiring reference memory, alpha1d-AR knockout mice showed normal spatial learning.

Magnetic resonance imaging shows delayed ischemic striatal neurodegeneration.

Brief focal ischemia leading to temporary neurological deficits induces delayed hyperintensity on T1-weighted magnetic resonance imaging (MRI) in the striatum of humans and rats. The T1 hyperintensity may stem from biochemical alterations including manganese (Mn) accumulation after ischemia. To clarify the significance of this MRI modification, we investigated the changes in the dorsolateral striatum of rats from 4 hours through 16 weeks after a 15-minute period of middle cerebral artery occlusion (MCAO), for MRI changes, Mn concentration, neuronal number, reactivities of astrocytes and microglia/macrophages, mitochondrial Mn-superoxide dismutase (Mn-SOD), glutamine synthetase (GS), and amyloid precursor protein.