Daily variations in the responses to papaverine but not theophylline in rat aorta

ULUOĞLU C., Hodoǧlugil U., GÜNEY H. Z., Görgün C. Z., Abacioǧlu N., Zengil H.

Biological Rhythm Research, vol.29, no.4, pp.343-352, 1998 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 29 Issue: 4
  • Publication Date: 1998
  • Doi Number: 10.1076/brhm.29.4.343.1428
  • Journal Name: Biological Rhythm Research
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.343-352
  • Keywords: rat aorta, ultradian rhythm, papaverine, theophylline, relaxation, endothelium, PHOSPHODIESTERASE INHIBITORS, BLOOD-PRESSURE, GUINEA-PIG, CYCLIC-AMP, 24-HOUR VARIATIONS, HYPERTENSIVE RATS, CIRCADIAN-RHYTHMS, ENDOTHELIUM, SYSTEM, RELAXATION
  • Lokman Hekim University Affiliated: No

Abstract

The presence of temporal patterns in the responses of vascular smooth muscle to relaxing agents have been known. The aim of this study was to examine the variations in the in vitro sensitivity of rat aorta to papaverine and theophylline in both endothelium-intact and -denuded rings. The animals were synchronized with a 12-h light: 12-h dark schedule. Rat thoracic aorta rings were obtained from animals sacrificed at six different times (09:00, 13:00, 17:00, 21:00, 01:00 and 05:00)of the day. Tissues were precontracted submaximally with phenylephrine and then were relaxed by papaverine (10-8- 10-4 M) and theophylline (10-7-10-3 M) applied cumulatively. The responses to most of the concentrations and EC50 values for papaverine demonstrated an ultradian rhythm with an 8 h periodicity. Time-dependent variations were not found in the responses to theophylline. The results are discussed in relation with the time-dependent differences in signal transducing mechanisms.