Uptake and subcellular distribution of intraventricularly injected [1-3H]dolichol in rat brain

The uptake of C95[1-3H]dolichol in the form of liposomes into rat brain after the intracerebral and intraperitoneal injection was investigated. Efficient, time-dependent uptake of dolichol into the brain was observed exclusively after the intraventricular injection. Within 24 h after the injection about 10% of the applied dolichol was found in the brain and 1.5% in liver. The distribution of dolichol in various parts of rat brain decreased in the order: cerebellum greater than midbrain greater than grey matter and brain stem greater than white matter. Seven days after the injection total radioactivity in the brain decreased and concomitantly a significant increase was observed in blood circulating and liver of the rat. The highest activity was found in grey matter and it remained a few times higher in comparison with that in white matter. About 80% of the dolichol taken up by the brain membrane was recovered in the following subcellular fractions: crude nuclear fraction greater than microsomes greater than mitochondria greater than synaptosomes greater than myelin. These results demonstrate for the first time that dolichol is actively taken up by the brain membrane exclusively after intraventricular injection of dolichol-phosphatidylcholine in the form of liposomes; this method may be useful in studies on the role of dolichol in brain function.