The “sacral parasympathetic”: ontogeny and anatomy of a myth

Abstract

We recently defined genetic traits that distinguish sympathetic from parasympathetic neurons, both preganglionic and ganglionic (Espinosa-Medina et al., Science 354:893–897, 2016). By this set of criteria, we found that the sacral autonomic outflow is sympathetic, not parasympathetic as has been thought for more than a century. Proposing such a belated shift in perspective begs the question why the new criterion (cell types defined by their genetic make-up and dependencies) should be favored over the anatomical, physiological and pharmacological considerations of long ago that inspired the “parasympathetic” classification. After a brief reminder of the former, we expound the weaknesses of the latter and argue that the novel genetic definition helps integrating neglected anatomical and physiological observations and clearing the path for future research.

The Clinical Autonomic Research journal 2018 and onward

“…For instance, this issue of the journal includes a review by Dr. Jean-François Brunet, who recently proposed a world-shattering re-classification of the autonomic pathways [1]. As expected, not everybody agrees with Dr. Brunet, and, also in this issue, we include counterpoint comments by Dr. Wilfrid Jänig and Dr. Frances Lefcort.…”

The sacral autonomic outflow: against premature oversimplification

“…This idea seemingly challenges the traditional view established originally by Langley [2,3] that the peripheral parasympathetic and sympathetic pathways are defined anatomically by the location of the preganglionic neurons in the spinal cord and brain stem. Now Espinosa-Medina and co-workers [2] critically review the arguments put forward more than 100 years ago by Gaskell, Langley and their followers. They come to the conclusion that their "reinterpretation of the sacral outflow in the light of embryonic development [namely as being in fact sympathetic]… [could be] a continuation of Gaskell´s and Langley´s vision".…”

“…Based on these data, they have put forward the idea that the preganglionic and postganglionic neurons of the autonomic nervous system in the sacral spinal cord and in the pelvic ganglia are sympathetic and not parasympathetic [1]. This idea seemingly challenges the traditional view established originally by Langley [2,3] that the peripheral parasympathetic and sympathetic pathways are defined anatomically by the location of the preganglionic neurons in the spinal cord and brain stem. Now Espinosa-Medina and co-workers [2] critically review the arguments put forward more than 100 years ago by Gaskell, Langley and their followers.…”

The Clinical Autonomic Research journal 2019 and onward

“…We are also renovating our commitment to scientific discussion, as we did in 2018 with, for instance, the topic on whether the sacral autonomic system is sympathetic or parasympathetic [7,8]. In this regard, this issue includes several papers on novel techniques for the assessment of sudomotor function, one of which, the electrochemical skin conductance, is not devoid of controversy [9][10][11].…”