'Autonomic' nervous system.

The functions of this system were elucidated in a series of important physiological experiments in the second half of the 19th century. Ernst and Eduard Weber in Leipzig stopped the heart by stimulating the vagus nerve whilst Claude Bernard and others reported the acceleration of the heart’s action with sympathetic stimulation. These opposing actions led Walter Gaskell [4] at Cambridge to conduct a series of experiments on heart physiology to conclude that the ‘involuntary system’ was composed of two antagonistic subsystems. Following reports by Oliver and Schäfer [5] in 1895 about the potent effects of adrenal gland extracts, research was focused on identifying ‘the active principle’. John Jacob Abel [6] working at Johns Hopkins in 1897 isolated a benzoyl derivative from crude adrenal extracts which he called ‘epinephrin’. He followed the suggestion of Josef Hyrtl, professor of anatomy at Vienna, that ‘epinephris’ was the best name for the suprarenal capsule. Hyrtl [7] preferred Greek to Latin, quoting Molière: ‘Parce qu’avec du grec on a toujours raison’. Jockichi Takamine [8] working in New York and sponsored by Parke Davis and Co. isolated the active principle in pure form and coined the term ‘adrenalin’. His colleague Thomas Aldrich successfully deduced its chemical structure and adrenalin became a trademarked name for Parke Davis. Subsequently scientific reports in American journals have used the term introduced by Abel, ‘epinephrine’ whereas European journals have used ‘adrenaline’. From the Oxford English Dictionary: ‘autonomic’ is the adjective derived from ‘autonomy’ meaning self-governing or independent [1] . With respect to physiology, autonomic nervous system is that part which functions independently of the will. John Newport Langley (1852–1925), the Cambridge physiologist, first applied the term in 1898 in a paper in the Journal of Physiology : ‘The autonomic nervous system means the nervous system of the glands and of the involuntary muscle ... I propose the term autonomic nervous system for the sympathetic nervous system and the allied nervous system of the cranial and sacral nerves, and the local nervous system of the gut’ [2] . The concept that an independent part of the nervous system coordinates body functions had its origin in the works of Galen (129–199), who proposed that nerves distributed spirits throughout the body. From animal dissections he concluded that there were extensive interconnections from the spinal cord to the viscera and from one organ to another. He proposed that this system fostered a concerted action or ‘sympathy’ of the organs. Little changed until the Renaissance when Bartolomeo Eustacheo (1545) depicted the sympathetic nerves, the vagus and adrenal glands in anatomical drawings. Jacobus Winslow (1669–1760), a Danish-born professor working in Paris, popularised the term ‘sympathetic nervous system’ in 1732 to describe the chain of ganglia and nerves which were connected to the thoracic and lumbar spinal cord [3] . Received: September 28, 2007 Accepted: November 2, 2007 Published online: July 30, 2008