title: Modulation of baroreflex function by rosiglitazone in prediabetic hyperglycemic rats.
abstract: Baroreflex sensitivity (BRS) is abnormal in the prediabetic state. This study was conducted to determine effects of chronic rosiglitazone (RSG), an insulin sensitizer, on BRS in prediabetic hyperglycemic (PDH) rats induced by nicotinamide and streptozotocin. The fasting and postprandial blood glucose levels were 5.6-6.9 and 7.8-11.0 mmol/l, respectively. Rats were treated with RSG or saline for 12 weeks. BRS response to phenylephrine (PE-BRS) or sodium nitroprusside (NP-BRS) was determined by linear regression method. Cardiac sympathetic and parasympathetic influences were determined by autonomic blockades. In the saline-treated PDH rats, PE-BRS was enhanced early at week 4 and became greater at week 12. Abnormalities in NP-BRS and cardiac autonomic influences were found only after week 12. Four weeks of RSG treatment normalized blood glucose levels but not PE-BRS. All altered cardiovascular variables were completely restored by 12 weeks of RSG treatment. The correlation between BRS and blood glucose levels in saline-treated PDH rats was significant at week 12, but no correlation was found in RSG-treated rats. In conclusion, hyperglycemia, even in the prediabetic state, may play a role in BRS abnormalities. RSG treatment early in the prediabetic state may normalize BRS via cardiac autonomic modulation, besides its anti-hyperglycemic action.
authors.affiliation: Department of Medical Education and Research, Taichung Veterans General Hospital, Taichung, Taiwan, ROC. lzhong@vghtc.gov.tw
authors.forename: L-Z
authors.initials: LZ
authors.lastname: Hong
authors.forename: Y-C
authors.initials: YC
authors.lastname: Chan
authors.forename: M-F
authors.initials: MF
authors.lastname: Wang
authors.forename: J-Y
authors.initials: JY
authors.lastname: Wang
authors.forename: S-W
authors.initials: SW
authors.lastname: Hung
authors.forename: C-I
authors.initials: CI
authors.lastname: Tsai
authors.forename: C-J
authors.initials: CJ
authors.lastname: Tseng
mesh_terms: D000818:Animals; D017704:Baroreflex / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects; D006943:Hyperglycemia / Q000188:drug therapy* / Q000503:physiopathology*; D007004:Hypoglycemic Agents / Q000008:administration & dosage; D011236:Prediabetic State / Q000503:physiopathology* / Q000517:prevention & control*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000008:administration & dosage*; D016896:Treatment Outcome
chemical_list: D007004:Hypoglycemic Agents; D045162:Thiazolidinediones; D000077154:Rosiglitazone