title: Responses of the retinal circulation to systemic autonomic stimulation in diabetes mellitus.
abstract: The retinal vessel calibre responses to systemic sympathetic stimulation, were studied in 22 randomly selected diabetic patients (mean age +/- SEM: 54.7 +/- 2.59 years, range 25-73; 13 IDDM, 9 NIDDM; 4 females), using sustained isometric muscle contraction as the stimulus. At a different session the integrity of the autonomic nerve function in these diabetic patients was assessed using 3 standard tests of autonomic nerve function, based on cardiovascular reflexes. Diabetic patients with an intact autonomic nervous system: Group 1, (n = 11, mean age: 54.9 +/- 4.55 years, 7 IDDM 4 NIDDM) showed a mean arteriolar constriction of 9.2% (SEM 2.89, p less than 0.01) and a mean venule constriction of 5.1% (SEM 1.73, p less than 0.02), for a mean rise in diastolic blood pressure of 23.7 mmHg (SEM 2.19 range: 13-33). There were no significant mean retinal vessel responses however, in diabetics with autonomic dysfunction (Group 2): mean arteriolar constriction of 1.2% (SEM 1.38 p greater than 0.05) and venule constriction of 2.1% (SEM 1.38, p greater than 0.05); for a mean rise in diastolic blood pressure of 19.8 mmHg (SEM 4.49, range: 2-50). There was no correlation between the rise in diastolic blood pressure and the retinal arteriolar constriction in the 2 groups (Group 1:r = 0.45, p greater than 0.01 and Group 2: r = 0.56, p greater than 0.05). Duration, type and control of diabetes were not significantly different between the 2 groups. The severity of retinopathy was slightly worse in Group 2 compared to Group 1. These results point to an association between autonomic neuropathy and failure of regulation of retinal blood flow.
authors.affiliation: Research Department of Ophthalmology, Royal College of Surgeons of England, London.
authors.forename: L P
authors.initials: LP
authors.lastname: Lanigan
authors.forename: C V
authors.initials: CV
authors.lastname: Clark
authors.forename: J
authors.initials: J
authors.lastname: Allawi
authors.forename: D W
authors.initials: DW
authors.lastname: Hill
authors.forename: H
authors.initials: H
authors.lastname: Keen
mesh_terms: D000328:Adult; D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001794:Blood Pressure; D003920:Diabetes Mellitus / Q000503:physiopathology*; D005260:Female; D005654:Fundus Oculi; D006339:Heart Rate; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D008875:Middle Aged; D012171:Retinal Vessels / Q000503:physiopathology*; D014661:Vasoconstriction