https://lsa.umich.edu/psych/research&labs/berridge/publications/Berridge&RobinsonBrResRev1998.pdf

What is the role of dopamine in reward: hedonic impact, reward learning, or incentive salience?

CNS plasticity and assessment of forelimb sensorimotor outcome in unilateral rat models of stroke, cortical ablation, parkinsonism and spinal cord injury.

VEGF is a secreted mitogen associated with angiogenesis and is also a potent vascular permeability factor. The biological role of VEGF in the ischemic brain remains unknown. This study was undertaken to investigate whether VEGF enhances cerebral microvascular perfusion and increases blood-brain barrier (BBB) leakage in the ischemic brain. Using magnetic resonance imaging (MRI), three-dimensional laser-scanning confocal microscope, and functional neurological tests, we measured the effects of administrating recombinant human VEGF(165) (rhVEGF(165)) on angiogenesis, functional neurological outcome, and BBB leakage in a rat model of focal cerebral embolic ischemia. Late (48 hours) administration of rhVEGF(165) to the ischemic rats enhanced angiogenesis in the ischemic penumbra and significantly improved neurological recovery. However, early postischemic (1 hour) administration of rhVEGF(165) to ischemic rats significantly increased BBB leakage, hemorrhagic transformation, and ischemic lesions. Administration of rhVEGF(165) to ischemic rats did not change BBB leakage and cerebral plasma perfusion in the contralateral hemisphere. Our results indicate that VEGF can markedly enhance angiogenesis in the ischemic brain and reduce neurological deficits during stroke recovery and that inhibition of VEGF at the acute stage of stroke may reduce the BBB permeability and the risk of hemorrhagic transformation after focal cerebral ischemia.

/pdf/vegf-enhances-angiogenesis-and-promotes-blood-brain-barrier-58r66iov9b.pdf

VEGF enhances angiogenesis and promotes blood-brain barrier leakage in the ischemic brain

Parkin-deficient Mice Exhibit Nigrostriatal Deficits but Not Loss of Dopaminergic Neurons

The unilateral 6-hydroxydopamine lesion model in behavioral brain research. Analysis of functional deficits, recovery and treatments.

We describe and demonstrate the usefulness of a reliable procedure for quantifying “sensorimotor” asymmetries in rats with nigrostriatal damage. Conventional tests, such as the popular Von Frey hair technique are sometimes inadequate in that positive responses are difficult to quantify, they are susceptible to subjective interpretation, and they require that the animal make head movements. Circling behavior has become established as a measure of asymmetrical nigrostriatal activity, but it does not measure stimulus-directed movement. One group of rats was given unilateral microinfusions of 6-OHDA into the nigrostriatal system which decreased levels of dopamine in the ipsilateral striatum and yieded an ipsilateral turning bias. Another group was given electrolytic lesions in the substantia nigra area, which yielded a severe contralateral circling bias. Small pieces of adhesive paper were applied to various parts of the limbs or snout and latencies to remove the stimuli were recorded. Because head and body movements were not required, assessment of stimulus-directed movement asymmetries could be quantified rapidly without the interference of stimulus-independent (“spontaneous”) postural and motor asymmetries. In the 6-OHDA-treated rats there was ipsilateral bias in stimulus-directed activity. Indeed, there was ipsilateral hyper-reactivity relative to sham controls. In rats with electrolytic nigra lesions, despite a strong contralateral “spontaneous” motor bias, there likewise was an ipsilateral bias in stimulus-directed movement, which could only be detected using the adhesive removal test. This similarity in stimulus-directed movement asymmetry between the two groups may reflect a common asymmetry in ascending dopaminergic pathways. The opposite circling bias following electrolytic nigra lesions may reflect differential damage to non-dopaminergic efferent projections. The bilateral adhesive removal (tactile extinction) test appears to permit the separate quantification of stimulus-directed and stimulus-independent movement asymmetries.

S. B. Farrar

Papers

Tactile extinction: distinguishing between sensorimotor and motor asymmetries in rats with unilateral nigrostriatal damage