|ketamine for depression? (source)|
1. Ketamine and the neurogenesis theory of depression. At a nice poster (324.28) R.M. Carter explained that ketamine has fast anti-depressant effects. Some people think that depression is caused by neurodegeneration and cured by neurogenesis (the growth of new neurons). So this group wanted to test whether ketamine could affect the growth of new neurons on the same timescale that ketamine affects depression (a few hours). And it does! Ketamine increased the rate that newly generated neurons in the dentate gyrus became synaptically mature. It will be interesting to see where this theory of depression goes. I would love to see a possible mechanism of action by which an NMDA antagonist could speed up neuron maturity. (Intuitively I would guess it would do the opposite.)
UPDATE 11/5/12: More on mechanisms of ketamine in synaptogenesis.
2. Fat and dopamine. In a nanosymposium (420.06) J. Carlin explained that rats fed a high fat diet from birth had lower dopamine than controls. This goes along with the idea that obesity can be related to a lower sensitivity to reward. The good news is that when the rats were put on a normal diet, the dopamine went back to normal. HOWEVER, this was only true for the males! The female rats did not go back to normal dopamine levels. Yikes, right? Carlin explained that maybe the females do go back to normal dopamine, but just not within the time frame that they tested. As always, more research is necessary.