During long-term space missions zero gravity has a great impact on all systems of a living organism. Scientists have previously studied changes, taking place in animal brain on the orbit, but all experiments were performed on Earth, when animals returned.
      
      Researchers from Russia and America united their efforts and performed unique experiment. American party has taken rats aboard “Columbia” and “SpaceLab-2” and, after two weeks in space, rat brains were fixed with a special solution and sliced. Then thin slices arrived to Earth, where Russian scientists were ready to investigate.
      
      Thin slices demonstrated even slightest changes in synapse structure and blood vessels – rat brain cortex showed reduced function of synapses. Moreover, their neuron processes degenerated, showing destruction of mitochondria (power stations of a cell). At the same time, blood vessel network in rat brain, which traveled to space, is unusually dense, and scientists explain this phenomenon with adaptation of an organism to zero gravity conditions – lack of information, getting to brain from muscles and other organs.
      
      Scientists noticed that brain structure of animals, which were examined two weeks after arrival, had almost no difference from that of rats, which stayed on Earth, due to regeneration processes, taking place in animal brain.
      
      Source: Science News