RT - Journal Article T1 - POTENTIATION OF RESPONSES TO UK-14304 IN RAT ISOLATED COMMON CAROTID ARTERY BY ANGIOTENSIN JF - MJIRI YR - 2001 JO - MJIRI VO - 15 IS - 2 UR - http://mjiri.iums.ac.ir/article-1-808-en.html SP - 83 EP - 88 K1 - α-adrenoceptors K1 - UK-14304 K1 - prazosin K1 - rauwolscine K1 - angiotensin II AB - The selective a2 -adrenoceptor agonist UK-14304 produces a small vasoconstrictor response in the rat isolated carotid artery. The purpose of the work presented here was to investigate whether stimuli that produce submaximal contraction would potentiate responses to UK-14304. Male Wistar rats were killed by overdose with pentobarbitone sodium, after which the left and right common carotid arteries were removed. The rings of arteries 3-4 mm in length were cut from each vessel and then mounted in 10 mL isolated organ bath, bathed in Krebs maintained at 37°C and gassed with 95% 02 plus 5% CO2, The preparations were allowed to equilibrate for an hour. Cumulative concentration-response curves (CCRC) were constructed in a cumulative manner by increasing the concentration of the agonists in half-log increments. When antagonists were used, the preparations were incubated at least for 45 minutes with the drugs prior to the onset of a second CCRC. Angiotensin II (All) and other contracting factors were added approximately 10-15 min prior to the onset of CCRC to an agonist. After inducing tone with low concentrations of the thromboxane A2 mimetic agent U-46619 (lnM), 5HT (0.5-1 ).lM) and phenylephrine (l0 nM), exposure of the preparation to UK-14304 resulted in concentration dependent conWrctions to this agonist. The sensitivity and maximum response of the preparation ,to' UK-14304 were not changed. Inducing tone with All (0.01 µM) produc􀁶d a significant leftward shift in the CCRC to UK-14304 (p LA eng UL http://mjiri.iums.ac.ir/article-1-808-en.html M3 ER -