By Joseph Knoll
The term “endogenous enhancer substance” is a synonym of “natural enhancer substance. It refers to brain constituents which increase the activity of special neurons which are sensitive to them, as for example, β-phenylethylamine (PEA) increases the activity of catecholamine producing neurons. The term was coined by Joseph Knoll in his monograph “The Brain and Its Self” published in 2005. The recognition that PEA is an “enhancer substance” and the introduction of the concept of “endogenous enhancer substance” was based on the finding that on a perfused rabbit central ear artery a low concentration of PEA did not affect smooth muscle resting tone but increased (enhanced) in a dose-dependent manner the muscle contractions in response to electrical stimulation (Knoll et al. 1996).
Knoll J. The Brain and Its Self. A Neurochemical Concept of the Innate and Acquired Drives. Springer, Berlin/Heidelberg/New York, 2005. pp.25-94
Knoll J., Miklya I.,Knoll B., Markó R., Rácz D. Phenylethylamine and tyramine are mixed acting sympathomimetic amines in the brain. Life Sciences 1996; 58:2101-2114