Moves aside St.John's Wort

I came across this recently and thought it tied in nicely to a discussion we had in a BIPH meeting a few weeks ago, while Seth was absent, regarding mind-altering drugs for the treatment of depression/anxiety/ADHD. 

 Lactobacillus rhamnosus 

Canadian researchers from  the Alimentary Pharmabiotic Centre in University College Cork, and the Brain-Body Institute at McMaster University have recently uncovered from their clinical studies of feeding  mice probiotic bacteria,  Lactobacillus rhamnosus JB-1 (which is found as a preservative in many yoghurt products and has a high immunity against strong acids found in the gut), that levels of the hormone corticosterone, which is stress induced, were notably lower than those of mice in the placebo group.

 It was also found that the stress-related and anxiety and depression-related behaviours were reduced in the trial group. Other results included noticeable changes in the GABA neurotransmitter receptors when mice were fed the probiotics on a regular basis. ( Bravo & Cryan, 2011) 

The findings highlight pathways of communication between the gastrointestinal tract and the brain, and is significant in possible developments of microbial treatments of anxiety or depression (Cryan, 2011) The changes in GABA neurotransmitter receptor expression is significant in highlight the direct influence of the probiotics on brain chemistry.

The communication between the microbes, the gastrointestinal tract and the brain is referred to as microbiome-gut-brain axis. Future studies on this network may open the door for probiotic treatment of more psychiatric illnesses and disorders. (ScienceDaily, 2011) 

Serotonin

I found this very interesting, considering the nature of current treatments for anxiety and depression, such as SSRIs (selective serotonin re-uptake inhibitors) or SNRIs (Serotonin Norepinepherin Re-uptake Inhibitors), which essentially inhibit the re-uptake of serotonin (or norepinepherin) resulting in a higher extracellular concentrations of the either neurotransmitter, so more is actually in the synapse to be able to bind to the postsynaptic receptors.

So the concept of using the microbiome-gut-brain axis for treatment effectively means that the receptors will be altered instead of the neurotransmitter concentrations.