The Effects Of Taurine And Its Combination With Other Drugs On Isolated Rat Thoracic Aorta From Different Age And Sex

OBJECTIVE To observe the effects of taurine, isoprenaline (Iso), acetylcholine (Ach), aminophylline (Ami) and the combinations of taurine with Iso, Ach or Ami on high K-induced pre-contractions of thoracic aorta rings isolated from rats of different age and sex. METHODS The effects of the drugs on rat isolated thoracic aortic rings' pre-contraction induced by 20 mmol/L KC1 were observed with MS2000 computer system. The rings were isolated from male or female Wistar rats aged 1, 3, 6 and 12 months respectively. RESULTS 1. Taurine increased the resting tone of thoracic aortic rings and showed contraction or relaxation of diverse potency on the per-contraction with different aging and different sex. 2. The relaxations to Iso, Ach and Ami are progressive weakening with aging. 3. Taurine produced an antagonism to Ach- or Ami-induced relaxation on the pre-contractions of the aortic rings of rats aged 1 month. 4. Taurine produced a relaxation about 54.85 16.91 % of the pre-contraction on aortic rings of male rats aged 3 months. 5. Taurine itself showed no effect, but enhanced the relaxation of Ach and Ami, and antagonized the contraction of Iso on aortic rings of female rats aged 3 months. 6. Taurine 20 mmol/L significantly increased the relaxation of Ami and reduced the contraction of Iso in aortic rings of rats aged 6 months. 7. Taurine reduced the contraction of Iso on aortic rings of male rats aged 12 months, with the maximal effect at 80 mmol/L taurine. 8. Taurine 20 mmol/L increased the relaxation of Ami in aortic rings of female rats aged 12 months. CONCLUSION Taurine increased the resting tone of the isolated rat thoracic aortic rings, but showed diverse actions on the pre-contraction with different age and sex. Iso, Ach and Ami showed relaxations on the pre-contraction and the relaxations are progressive weakening with aging, or even turn into a contraction. Preincubation with taurine, at most cases, showed an enhancement to the relaxation and an antagosim to the contraction with irregular potency on the rings from different age and different sex.