Mechanosensitivity: From Aristotle's sense of touch to cardiac mechano-electric coupling.

Scientific interest in mechanosensation likely commenced with Aristotle's description of the sense of touch in his treatise de Anima [On the Soul]. Considering touch as a vital sense distributed over the whole body, the philosopher outlined a "physiological concept" at the macro-level already 2400 years ago. From this starting point, we outline the onset of modern sensory physiology during the early 19th century. Physiologists distinguished between outer and inner senses at that time, without, however, referring to specific receptors or nerves. We then outline how research on four topics concerning cardiac mechano-electric coupling developed up until the 1960's (cardio-respiratory coupling, Bainbridge reflex, Bezold-Jarisch reflex, stretch-induced arrhythmias). Following the discovery of macroscopic phenomena (e.g. change of heart rate, induced by atrial distension) during that period, researchers sought to identify the pertinent receptors and reflex loops, while nowadays the underlying subcellular mechanisms such as stretch-activated ion channels are under investigation.