A detailed non-invasive study of systemic and regional haemodynamic responses to a range of autonomic tests which assess sympathetic and parasympathetic pathways (mental arithmetic, cutaneous cold, isometric exercise, deep breathing, Valsalva manoeuvre and head-up tilt) were performed in ten patients with secondary progressive multiple sclerosis and ten age- and sex-matched healthy normal subjects (controls). Blood pressure rose in controls during the pressor tests and was maintained during tilt. In six out of ten patients with multiple sclerosis blood pressure was unchanged during one or more of the three pressor tests, but was maintained in all during tilt. In the controls, superior mesenteric artery blood flow fell during pressor tests and head-up tilt. In multiple sclerosis patients, superior mesenteric artery blood flow did not change during pressor tests but fell during tilt. Cardiac index rose during isometric exercise and fell during head-up tilt in controls. Forearm blood flow rose during mental arithmetic in the controls only, but fell during tilt in both groups. Individual analysis indicated that of the ten multiple sclerosis patients, four had responses during the pressor tests similar to controls. Responses to deep breathing and to the Valsalva manoeuvre in controls and multiple sclerosis patients were similar. We conclude that some patients with an aggressive and disabling form of multiple sclerosis have selective autonomic dysfunction, in particular involving pressor responses, despite the lack of postural hypotension. The autonomic abnormality is likely to involve central autonomic interconnections rather than afferent or sympathetic efferent pathways. Further clarification of the nature, site and progression of these lesions is needed.(ABSTRACT TRUNCATED AT 250 WORDS)

Our results suggest that patients with MSA have GE rates similar to those of patients with PD, but slower than healthy age matched individuals. It remains to be investigated whether gastrointestinal dysfunction in MSA is related to both brain and peripheral pathology, as is presumed for PD.

Enhanced expression of beta-adrenoceptor densities on peripheral blood mononuclear cells (PBMCs) in progressive multiple sclerosis patients has been observed in a number of independent studies. A link between increased number of beta-adrenoceptors and inflammatory disease has been further indicated by studies in rheumatoid arthritis and relapsing-remitting multiple sclerosis patients. In a serial monthly assessment of relapsing-remitting multiple sclerosis patients, we have demonstrated that increased beta-adrenoceptors on PBMCs correlate with the expression of high affinity interleukin-2 receptors (IL-2Rs) and disease activity as determined by clinical and MRI findings. Magnetic resonance imaging activity was strongly correlated with IL-2R expression and it appears to be a sensitive marker of PBMC immunoactivation in multiple sclerosis. In vitro studies showed that beta-agonist stimulation of PBMCs reduces the IL-2R expression and suppresses cell proliferation following mitogenic stimulation. This observation may indicate a recovery role for the enhanced beta-adrenoceptor expression in multiple sclerosis. However, its therapeutic importance remains to be tested by appropriate trials using either beta-agonists or agents activating the second messenger system, c-AMP, in lymphocytes.

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