Medical Journal of the Islamic Republic Of Iran
مجله پزشکی جمهوری اسلامی ایران
Med J Islam Repub Iran
Medical Sciences
http://mjiri.iums.ac.ir
2
journal2
1016-1430
2251-6840
8
10.18869/mjiri
14
8888
13
en
jalali
1380
5
1
gregorian
2001
8
1
15
2
online
1
fulltext
en
POTENTIATION OF RESPONSES TO UK-14304 IN RAT ISOLATED COMMON CAROTID ARTERY BY ANGIOTENSIN
Physiology
Physiology
Original Research: Basic Science in Medicine
Original Research: Basic Science in Medicine
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) producd
a significant leftward shift in the CCRC to UK-14304 (p<0.05). Thus
submaximal contraction with All (0.01 µ M) increased responses significantly,
but inducing tone with phenylephrine, U-46619 and 5HT had no
effect on responses to UK-14304. The α-adrenoceptor antagonists prazosin
and rauwolscine were examined to see whether UK-14304's main action
in the presence of All remained via al. The potentiated responses were
. prazosin sensitive and rauwolscine resistant, indicating an increasing effect
mediated by al-adrenoceptors.
α-adrenoceptors, UK-14304, prazosin, rauwolscine, angiotensin II
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http://mjiri.iums.ac.ir/browse.php?a_code=A-10-298-263&slc_lang=en&sid=1
M
MOHAMMADI NAGHADEH
20031947532846004182
20031947532846004182
Yes
From the Department of Physiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, I.R. Iran
JC
McGRATH
20031947532846004183
20031947532846004183
No
the Clinical Research Initiative in Heart Failure, West Medical Building, University of Glasgow, Glasgow G21-BQQ, Scotland.