Abstract
Weaver (gene symbol wv) is an autosomal recessive mutation in the mouse that causes the death of neurons in the cerebellum and of dopamine- containing neurons in the mid-brain. In the accompanying paper and in previous reports, the selective nature of the deficit produced by the gene in the dopamine-containing systems has been described after analysis of the patterns of the residual innervation in the striatum and the patterns of cell death in the midbrain. In the present report, we describe deficits in the terminals of the mesostriatal system occurring prior to a detectable dopamine deficiency in the striatum and prior to the onset of cell death in the mesencephalic dopamine- containing neurons during development. We have also found deficits in the remaining terminals of the adult weaver's striatum after the weaver pattern of innervation has been permanently established. Axonal terminals in the caudoputamen are impaired in weaver mice at postnatal day 7, before the onset of dopamine depletion in the caudoputamen and cell death in the midbrain. The impairment was revealed by a markedly deficient high-affinity uptake for 3H-dopamine by synaptosomes prepared from the caudoputamen. Throughout the remainder of development and in adulthood, the extent of the deficit in 3H-dopamine uptake was always greater than that for dopamine content. No striatal region was completely spared the effects of the gene. In the nucleus accumbens of the weavers, where dopamine content is normal, 3H-dopamine uptake was reduced by 35% in the synaptosomal preparations. In the olfactory tubercle, dopamine levels were reduced by 44% but 3H-dopamine uptake was reduced by 60%.(ABSTRACT TRUNCATED AT 250 WORDS)
