Depressed ventilatory reflexes after capsaicin challenge in streptozotocin-treated rats.
Diabetic sensory neuropathy is an affliction that decreases sensory perception in a number of organ systems. Although little is known of its pulmonary effects certain diabetic patients have reduced airway reactivity to cold air and elevated cough threshold to irritant inhalation, reflexes reported to be mediated by pulmonary C-fibers. Therefore we studied the effects the selective C-fiber activator capsaicin (0.01% aerosol, 30 s) on variables of ventilation using a whole-body plethysmograph in age-matched rats treated with streptozotocin (STZ) or its vehicle at 6 and 12 weeks after treatment. Body weight increased and plasma glucose and glycosylated hemoglobin were stable in vehicle-treated rats. In STZ-treated rats body weight decreased and plasma glucose and glycosylated hemoglobin increased. Capsaicin challenge decreased tidal volume, respiratory rate and therefore minute ventilation in non-treated and vehicle-treated rats. However capsaicin challenge increased tidal volume thereby altering minute ventilation in STZ-treated rats. Specific airway resistance increased in both groups after capsaicin challenge. Changes in ventilation in response to capsaicin challenge in STZ-treated rats may involve C-fiber sensory neuropathy.
Department of Biomedical Sciences, School of Medicine Creighton University, 2500 California Plaza, Omaha, NE 68178, USA. dbergren@creighton.edu
Dale R
DR
Bergren
Marc S
MS
Rendell
D000704:Analysis of Variance; D000818:Animals; D001786:Blood Glucose; D001835:Body Weight; D002211:Capsaicin / Q000494:pharmacology*; D003371:Cough / Q000139:chemically induced; D003921:Diabetes Mellitus, Experimental / Q000150:complications*; D003929:Diabetic Neuropathies / Q000150:complications / Q000503:physiopathology*; D004195:Disease Models, Animal; D006442:Glycated Hemoglobin / Q000378:metabolism; D008297:Male; D036421:Nerve Fibers, Unmyelinated / Q000187:drug effects; D010993:Plethysmography, Whole Body; D012123:Pulmonary Ventilation / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013311:Streptozocin; D013990:Tidal Volume / Q000187:drug effects; D013997:Time Factors
D001786:Blood Glucose; D002211:Capsaicin; D006442:Glycated Hemoglobin; D013311:Streptozocin