The responses to manipulation of extracellular and intracellular calcium are altered in the streptozotocin-diabetic rat colon and ileum.
Studies were performed to see if alterations in Ca2+ homeostasis underlie the gastrointestinal motility complications seen in many diabetic patients. Experiments were performed on colonic and ileal tissues taken from streptozotocin-induced diabetic and control rats. Diabetes caused alterations in the responses of the tissues to Ca2+ manipulation but these differed between the colon and ileum. In the colon a small but not significant increase in contractile responses to CaCl2 was observed in diabetic tissues, whereas the responses of the ileum were depressed relative to those of the controls. In contrast, responses of the diabetic ileum to the Ca2+ channel agonist Bay K8644 were greater than those of the controls, whilst the agonist failed to contract the colon. Similarly, the Ca2+-ATPase inhibitors, thapsigargin and cyclopiazonic acid, produced contractions which were greater in diabetic ileal tissues. Thus, alterations in the responses of the diabetic gut to Ca2+ manipulation are complex, and also tissue-specific.
Forrest
Abigail
A
The School of Life Sciences, University of Hertfordshire, CP Snow Building, College Lane, Hatfield, Herts AL10 9AB, United Kingdom.
Molleman
Areles
A
Parsons
Mike
M
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002122:Calcium Chloride / Q000494:pharmacology; D020013:Calcium Signaling / Q000502:physiology*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000494:pharmacology; D044682:Colon, Ascending / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007082:Ileum / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D007211:Indoles / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D009543:Nifedipine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013311:Streptozocin / Q000008:administration & dosage / Q000009:adverse effects*; D019284:Thapsigargin / Q000494:pharmacology; D013997:Time Factors
D007211:Indoles; D000001:Calcimycin; D013311:Streptozocin; D019284:Thapsigargin; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D000252:Calcium-Transporting ATPases; D009543:Nifedipine; D002122:Calcium Chloride; C000543:cyclopiazonic acid