Figure 1.

Proposed β-endorphin influence on adult neurogenesis following exercise. During multiple types of exercise, β-endorphins are released peripherally, which may signal in the dentate gyrus either through transport across the blood–brain barrier (BBB) or direct infusion into cerebrospinal fluid (CSF) and to the hippocampus via volume transmission. Once at the dentate gyrus, β-endorphins may enhance cell proliferation by both directly inducing proliferative activity in progenitor cells from acting on mu opioid receptors (MOR), which upregulate during exercise, or enhancing local net excitation by inhibiting GABAergic interneurons.