Figure 1.

Hypothesized pathway linking meat consumption and neuronal activity. IGF-1 increases with the consumption of animal protein. Within the adrenal gland, IGF-1 prevents apoptosis of cells thus increasing the centripetal movement of cells from the Zona Glomerulus (ZG) and Zona Fascularis (ZF) into the Zona Reticularis (ZR). Increased IGF-1 would result in a thicker ZR and greater production of DHEA/S. DHEA/S crosses the blood brain barrier and enters into neurons. Within the neuron, DHEA acts at the Sigma-1 Receptor located on the mitochondrial associated membrane between the mitochondria and the endoplasmic reticulum. Activation of the Sigma-1 receptor acts to increase energy production and alleviate stress-related production of oxygen free radicals. The result is the increased production and release of neurotransmitters as suggested by the arrows along the axon.