The rhythm of the heart — the tempus of music — Mozart, Ligeti and the Rat

Abstract

Almost all physiological functions of living organisms, including man, are characterised by regular circadian variations (Aschoff 1963, Reinberg and Smolensky 1983, 1989, Lemmer 2004). Descriptions of rhythmical biological processes were reported already 300 years ago, so we cannot regard this area of study as a recently discovered one. However, today there is scientific evidence available which confirms the existence of ‘biologic clocks’ governing the circadian/biological rhythms down to the level of molecular biology. So-called ‘clock genes’ have been discovered in almost all cells, whereby the ‘master clock’ is situated in the core area of the nucleus suprachiasmaticus (SCN) in the brain. A rhythm of this kind is referred to as ‘circadian’ (circa, dies, i.e. approximately one day) if it is maintained by an inner mechanism even in the absence of external time cues, for instance, during a period of permanent darkness. However, the term is generally used in a wider sense as well, simply denoting a 24-hour rhythm. Circadian rhythms can be demonstrated to exist for systematic functions (blood pressure, pulse, organ functions, mental processes, etc.) down to the levels of hormonal activity, receptors and signal transduction processes between and within cells, enzyme kinetics and gene regulation. Man, too, is an organism whose functions are completely organised according to chronobiological patterns. Pathophysiological events such as heart attacks, angina pectoris, strokes, asthma attacks, allergic reactions, rheumatic complaints, gastrointestinal ulcers and so forth do not occur at random the 24 hours of the day, but rather take place according to a prominent circadian rhythm (Lemmer 1989, 2004).