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In mammals, sweating is a multifunctional response that aids in locomotion, thermal regulation, self-protection, and communication of psychological state. Humans possess three types of sweat glands (apocrine, eccrine, and apoeccrine) that are differentially distributed on the body surface and make unique contributions to these distinct functions of the sweating response. In humans, eccrine glands, which are widely distributed on hairy skin, play an important role in thermoregulation. They are also found on the glabrous skin of the palm and sole, where they are not usually activated by heat, but rather by deep respiration, mental stress, and local tactile stimulation. Sweating on the palm and sole, so-called "emotional sweating", acts to prevent slippage while grasping or performing a delicate task using the fingertips. Although the central pathways of emotional sweating are not yet elucidated in detail, it is thought that the amygdala, cingulate cortex, and medulla participate via efferent fibers that descend through the spinal cord and connect to preganglionic sympathetic neurons in the nucleus intermediolateralis. The limbic system, including the amygdala and cingulate cortex, is critical for emotional processing and many cognitive functions. Thus, measurement of sweat output on the palm or sole is useful for evaluating sympathetic function and limbic activity in autonomic and psychiatric disorders.

The discovery of acetylcholine was closely related to research on the autonomic nervous system. At the onset of the twentieth century, John Newport Langley (1852-1925), a patriarch of modern autonomic research, classified the autonomic nervous system into the sympathetic, parasympathetic, and enteral systems, proposed the concept of preganglionic and postganglionic autonomic nerves, and suggested the presence of a "receptive substance" allowing the interaction of postganglionic nerve terminals and effector visceral organs. Around the same time, Henry Hallett Dale (1875-1968) revealed the pharmacological properties of acetylcholine, and he and his colleague, Wilhelm Feldberg (1900-1993), demonstrated that acetylcholine acts as a mediator of nerve impulses across nerve junctions (synapses) between nerves (sympathetic ganglia), and between the vagus nerve and heart (parasympathetic nerve terminals). On the other hand, Bradbury and Eggleston first described 3 patients with orthostatic hypotension in 1925, introducing the term "idiopathic orthostatic hypotension". However, this term was used loosely. Therefore, Roger Bannister proposed "pure autonomic failure" as the term for idiopathic orthostatic hypotension without other neurological symptoms. Recently, autoimmune autonomic ganglionopathy associated with anti-ganglionic acetylcholine receptor antibodies has attracted attention as a differential diagnosis of pure autonomic failure, which is characterized by Lewy body pathology.

Parkinson's disease (PD) is a progressive neurodegenerative disorder characterised by motor dysfunction (parkinsonism) and several non-motor features. Dysautonomia is a significant non-motor feature as well as a neuropsychiatric symptom. Autonomic dysfunction can occur even in the early stages of PD, often preceding the onset of the classic motor symptoms of PD. The patterns of autonomic features in PD are different from other parkinsonian disorders. Detection of autonomic dysfunction may therefore be helpful in diagnosing PD in the early or pre-motor stages, and/or in differentiating it from other parkinsonian disorders, such as multiple system atrophy and progressive supuranuclear palsy. The aim of this review is to describe aspects of autonomic dysfunction, including symptoms, assessment and pathophysiology, resulting from autonomic impairment in PD and other parkinsonian syndromes.

Although the clinical symptoms of Machado-Joseph disease (MJD) vary widely, those involving the autonomic nervous system, such as cutaneous sympathetic dysfunction, have rarely been investigated. In addition, there are no reports on cutaneous vasomotor function in patients with MJD. To determine the effects of MJD on cutaneous sympathetic function, we evaluated cutaneous vasomotor and sudomotor responses in the palms of 15 patients (mean age, 49 ± 15 years; seven men and eight women) who were genetically diagnosed with MJD as well as in the palms of 15 age-matched, healthy controls (mean age, 48 ± 16 years; nine men and six women). Sweat response was absent in 10 (67 %) patients with MJD, and the mean amplitude of sweat response was significantly lower (p<0.0001) in patients with MJD than in healthy controls following mental stress (mental arithmetic) and physiological stimuli. Although vasoconstrictive response was absent in three patients with MJD (20 %), there were no significant differences in the mean amplitude of vasoconstrictive response between patients with MJD and healthy controls. These results indicate that patients with MJD have reduced cutaneous sympathetic response, including severely impaired sudomotor functions and mildly affected vasomotor functions.

The cardiovascular system is regulated by cortical modulation such as the anterior cingulate gyrus, insular cortex, amygdala as well as the reticular formation of the brainstem, including ventrolateral medulla (vasopressor center). These structures are called as the central autonomic network (CAN), and its dysfunction causes autonomic dysregulation. For example, ventrolateral medulla compression by tortuous or ectatic vessels has been etiologically linked with essential hypertension. In regard to a relationship of the cerebral cortex and autonomic dysfunction, hypoperfusion of the anterior cingulate gyrus may be seen in patients with chronic autonomic failure such as pure autonomic failure. Meanwhile, patients with chronic hypertension may also show hypoperfusion of the anterior cingulate gyrus. These findings indicate that inadequate internal environment such as hypotension and hypertension in long term can reduce activities of the anterior cingulate gyrus. In regard to the insular cortex, a relationship with cardiac events or sudden death has drawn attention but now it may be time to revaluate this relationship. Amygdala also play an important role in autonomic regulation. Patients with bilateral amygdala damage show s poor autonomic response to mental stress which induces emotional change.

Uro-neurological assessment was performed in four patients with small-fiber neuropathy due to amyloidosis (2 transthyretin-type/2 immunoglobulin light-chain-type). Voiding difficulties were due to detrusor weakness and impaired bladder sensation. In two patients cholinesterase inhibition treatment caused urge incontinence, indicating detrusor denervation supersensitivity. The underlying mechanisms of urinary dysfunction seem to involve postganglionic cholinergic and afferent somatic nerves.

Abstract: Aim: We systematically performed autonomic testing on patients with polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes syndrome (POEMS) to determine whether autonomic function is preserved in such patients. Methods: We studied 17 POEMS patients, 17 diabetic neuropathy (DN) patients and 17 age-matched normal subjects. Blood pressure responses to the head-up tilt test and heart rate variability were used to evaluate cardiovascular autonomic function. Sweat responses and cutaneous vasoconstriction to several stimuli were recorded via the finger tips to estimate cutaneous sympathetic function. In addition, motor nerve conduction studies were performed. Results: Although the results of the autonomic testing were normal in POEMS patients, motor disability was severe, and motor nerve conduction studies provided evidence of extensive axonal loss. The DN patients showed significantly impaired autonomic responses despite mild motor dysfunction. Conclusions: Autonomic function was normal in POEMS patients, indicating the preservation of autonomic fibers and selective involvement of large fibers. [Copyright &y& Elsevier]

In order to evaluate gastric motility and its circadian rhythm in patients with multiple system atrophy (MSA) and healthy control subjects, we measured gastric myoelectrical activity (GMA) for 24 hours using a cutaneous electrogastrogram (EGG) recorder in 14 MSA patients and 9 age-matched controls.We analyzed six 10-minute segments of EGG before and after each meal and two 20-minute EGG segments during sleep; three parameters were used for the analysis: dominant frequency (DF), instability coefficient of dominant frequency (ICDF), and dominant power (DP). DF increased during daytime and decreased during sleep in the control, while this circadian variation was blunted in the patients with MSA. The average DF of the eight segments in the MSA patients did not differ from that of the control. Both MSA patients and control subjects did not show the circadian variation of ICDF and DP. The average ICDF of the eight segments in the patients with MSA was significantly decreased when compared with that of the control (p<0.01). No differences were observed in DP between the two groups. This study indicates that the healthy subjects appear to have a circadian rhythm of DF, and the patients with MSA appear to have impaired circadian rhythm of DF and decreased ICDF possibly due to the degeneration of the central autonomic neurons. [ABSTRACT FROM AUTHOR]

A 64 year-old woman developed Raynaud's phenomenon and dry eyes/mouth. Laboratory examination revealed positive Schirmer's test, rheumatoid factor and anti-nuclear antibody, and lymphocytic sialoadenitis on salivary gland biopsy. These features strongly suggested the diagnosis of primary Sjogren's syndrome. Three years later, she gradually developed generalized autonomic failure without apparent sensory neuropathy on nerve conduction study. She had systolic pressure fall of 51 mmHg on head-up tilt test, cardiovascular supersensitivity to diluted norepinephrine infusion, cardiac denervation in [123I]-MIBG scintigraphy, impaired R-R variability, decreased sweating and prolonged colonic transit time. Autoimmune autonomic ganglionopathy was mostly responsible for her autonomic failure. [ABSTRACT FROM AUTHOR]