Effects of streptozotocin-induced diabetes and insulin treatment on substance P of the rat arterial wall.
Substance P (SP) is present in perivascular nerves throughout the mammalian vasculature. Reports of diminished SP levels in nerve and gastrointestinal tissues of diabetic rats led us to examine SP-like immunoreactivity (SP-LI) in large arteries by RIA. Six weeks after inducing diabetes with streptozotocin (STZ), SP-LI was measured in the thoracic aorta, abdominal aorta, and the proximal superior mesenteric artery. In diabetics we measured a doubling (P<0.01) of SP-LI in all three artery wall preparations. This finding was verified in a second experiment which included a subset of diabetics treated daily with insulin for the sixth week of the holding period. Again, we measured a two-fold or greater increase of SP-LI (P<0.01-0.05) in arteries from the diabetics and found that insulin treatment significantly reduced SP-LI (P<0.05). In contrast to reports of diminished SP content in other tissues of diabetic rats, our findings demonstrate that the artery wall experiences at least a two-fold increase of SP-LI in the diabetic state. Furthermore, this elevation of SP-LI is reduced by insulin. We speculate that these changes of arterial wall SP-LI may contribute to altered regulation of the vascular system in the diabetic state.
Markle
R A
RA
Physiology and Functional Morphology Group, Department of Biological Sciences, Northern Arizona University, Flagstaff 86011-5640, USA.
Walker
D K
DK
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism; D001158:Arteries / Q000187:drug effects* / Q000378:metabolism*; D001786:Blood Glucose / Q000187:drug effects / Q000378:metabolism; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D002211:Capsaicin / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy* / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013373:Substance P / Q000276:immunology / Q000378:metabolism*
D001786:Blood Glucose; D007328:Insulin; D013373:Substance P; D002211:Capsaicin