Mesencephalic dopaminergic neurons protected by GDNF from axotomy-induced degeneration in the adult brain

Transforming growth factor-beta 1 levels are elevated in the striatum and in ventricular cerebrospinal fluid in Parkinson's disease

Transforming growth factor (TGF)-beta 1 content was measured for the first time in the brain (caudate nucleus, putamen, and cerebral cortex) and in ventricular cerebrospinal fluid (VCSF) from control and parkinsonian patients by a sandwich enzyme immunoassay. The concentrations of TGF-beta 1 were significantly higher in the dopaminergic striatal regions in parkinsonian patients than those in controls, but were not significantly different in the cerebral cortex between parkinsonian and control patients. Furthermore, the concentrations of TGF-beta 1 in VCSF were significantly higher in parkinsonian patients than those in non-parkinsonian control patients. Since TGF-beta 1 has potent regulatory activity on cell growth, these results suggest that TGF-beta 1 may have some significant modulatory role in the process of neurodegeneration in Parkinson's disease.

Potent inhibitory effects of glial derived neurotrophic factor against kainic acid mediated seizures in the rat

Recently messenger RNA (mRNA) for glial derived neurotrophic factor (GDNF), a recently discovered member of the TGF-beta superfamily, was shown to increase in the hippocampus after kainic acid-induced seizures. The possibility that exogenous recombinant human (rh) GDNF may have anticonvulsant properties was investigated using a model of temporal lobe epilepsy in the rat. rhGDNF, vehicle or inactive rhGDNF were injected intracerebroventricularly 1 h before peripheral administration of kainic acid. rhGDNF suppressed kainic acid-induced tonic-clonic convulsions when compared to animals treated with vehicle or inactive rhGDNF. The inhibition of kainic acid-induced seizure activity by rhGDNF also prevented the associated neuronal cell loss in hippocampal, thalamic and amygdaloid regions. These results suggest that rhGDNF should be evaluated in other seizure and acute neural disorders that are associated with excitotoxic processes.

Sensory but not motor neuron deficits in mice lacking NT4 and BDNF

Neurotrophins play important roles in neuronal survival during vertebrate development. Neurotrophin-4 (NT4), alone or in combination with brain-derived neurotrophic factor (BDNF), has been suggested to be necessary for the survival of peripheral sensory neurons and central nervous system (CNS) neurons, including motor neurons. To define the role of NT4 in vivo, we generated mice lacking NT4 by gene targeting. NT4-deficient mice were viable but exhibited a loss of sensory neurons in the nodose-petrosal and geniculate ganglia. In contrast, motor neurons of the facial nucleus and sympathetic neurons of the superior cervical ganglion were unaffected, and there was no obvious loss of dopaminergic neurons in the substantia nigra. In mice lacking both NT4 and BDNF, facial neurons remained unaffected, whereas the loss of sensory neurons was more severe than with either mutation alone. Thus NT4 is required during development for the survival of some peripheral sensory neurons but not sympathetic or motor neurons.