Increased responsiveness of sensory neurons in the saphenous nerve of the streptozotocin-diabetic rat.
1. This study examined sensory neurons in the saphenous nerve of rats treated with streptozotocin to induce diabetes (STZ-D). Several physiological properties of sensory neurons were not significantly different in STZ-D compared with control (CON) rats, including percentage and rate of spontaneous activity seen in the whole nerve and mechanical and thermal thresholds of individual C-fibers. 2. The response of STZ-D and CON C-fibers to a sustained (1 min) mechanical stimulus of threshold force was similar. However, during the 5 min immediately after removal of this stimulus, there was a much greater afterdischarge in STZ-D rats (STZ-D: n = 35; 14.6 +/- 5.1 action potentials/5 min, mean +/- SE; CON: n = 34; 3.9 +/- 0.7 action potentials/5 min). The number of action potentials during a sustained (1 min) suprathreshold mechanical (445 g) stimulus was also significantly greater in the C-fibers from STZ-D rats (STZ-D: n = 44; 149.7 +/- 18.4 action potentials; CON: n = 45; 84.7 +/- 12.2 action potentials). The afterdischarge during the 5 min immediately after removal of the sustained suprathreshold stimulus was also greater in C-fibers from STZ-D rats (STZ-D: 38.7 +/- 13.1 action potentials/5 min; CON: 9.3 +/- 2.3 action potentials/5 min). 3. There was a significant difference between C-fibers from STZ-D and CON rats with respect to the distribution among certain sensory classes.(ABSTRACT TRUNCATED AT 250 WORDS)
Ahlgren
S C
SC
Department of Anatomy, University of California, San Francisco 94143.
White
D M
DM
Levine
J D
JD
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D004594:Electrophysiology; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology; D009412:Nerve Fibers / Q000502:physiology; D009413:Nerve Fibers, Myelinated / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology*; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D012684:Sensory Thresholds / Q000502:physiology