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Intraneural stimulation elicits an increase in subcutaneous interstitial glycerol levels in humans
Author(s) -
Dodt Christoph,
Lönnroth Peter,
Fehm Horst Lorenz,
Elam Mikael
Publication year - 1999
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1999.00545.x
Subject(s) - stimulation , microdialysis , lipolysis , subcutaneous tissue , fascicle , femoral nerve , adipose tissue , subcutaneous adipose tissue , medicine , glycerol , neurostimulation , fat pad , anatomy , subcutaneous injection , endocrinology , chemistry , pathology , central nervous system , organic chemistry
1 The effect of intraneural electrical stimulation of the lateral femoral cutaneous nerve on lipolysis in the innervation territory of the stimulated nerve fascicle was studied in seven healthy women. Lipolysis was evaluated by microdialytic measurement of the interstitial glycerol concentration in subcutaneous adipose tissue. 2 Ten minutes of unilateral intraneural stimulation elicited a 22 ± 8 % (mean ± s.e.m.s ) increase in glycerol levels in the stimulated region ( P < 0.05 ), whereas no change was registered in the corresponding area of the contralateral unstimulated leg. 3 Significantly higher glycerol levels in the stimulated vs. contralateral unstimulated region (47 ± 13 %, P < 0.05 ) were already observed at baseline (30 min resting period preceding the 10 min stimulation), in all probability as a consequence of the nerve searching procedure and trial stimulations. After the 10 min stimulation, the overall glycerol increase was 72 ± 17 % compared with the contralateral leg, illustrating the degree of lipolysis induced by the whole experimental procedure. 4 The sympathetic discharge in the lateral femoral nerve (6 recordings) showed typical characteristics of skin sympathetic activity, and the firing pattern was strikingly similar to simultaneously recorded sympathetic discharge in cutaneous nerve fascicles innervating regions without prominent subcutaneous fat stores (2 double nerve recordings). Thus, no component of cutaneous sympathetic outflow specific for the nerve innervating prominent subcutaneous fat stores could be identified. 5 Our findings suggest that sympathetic nerve fibres travelling in cutaneous nerve fascicles exert a regulatory influence on subcutaneous fat tissue in humans. The combination of intraneural recording/stimulation and subcutaneous microdialysis provides a model for evaluating neural control of human fat metabolism.