5-HT1B receptor augmented 5-HT vasoconstrictor response of pulmonary artery in monocrotaline-induced pulmonary hypertensive rats.
OBJECTIVE
To study the relationship between the vasoconstrictor effect to 5-hydroxytryptamine (5-HT) and the expression of 5-HT1B-and 5-HT1D)-receptors in pulmonary arteries (PA) from normal and pulmonary hypertensive (PHT) rats.


METHODS
Monocrotaline (MCT)-treated rats were used as a model for chronic PHT. Concentration-response curves of 5-HT induced pulmonary vasoconstriction were established and semiquantitative RT-PCR was performed to identify mRNA expression of 5-HT1B- and 5-HT1D-receptors in rat PA.


RESULTS
5-HT induced vasoconstrictor response of PA from MCT rats was enhanced (Emax) 50 % +/- 20 % vs control 38 % +/- 21 %, P < 0.05). A significantly higher level of 5 -HT1B receptor mRNA expression was detected in PA from MCT rats. The ratio of the PCR products of 5-HT1B receptor gene to those of beta-actin gene was much higher in MCT rats than that in control rats (0.43 +/- 0.14 vs control 0.27 +/- 0.15, P < 0.05).


CONCLUSIONS
5-HT1B receptor is involved in pulmonary vasoconstriction and the enhanced level of 5-HT1B receptor mRNA expression is closely related to the augmentation of 5-HT induced pulmonary vasoconstriction in PHT rats.
Wang
H L
HL
Department of Clinical Pharmacology, China Medical University, Shenyang 110001, China. hlwang@mail.cmu.edu.cn
Dong
X
X
Zhang
X H
XH
Xing
J
J
D000818:Animals; D006976:Hypertension, Pulmonary / Q000139:chemically induced / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D016686:Monocrotaline; D011651:Pulmonary Artery / Q000378:metabolism / Q000503:physiopathology*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D044302:Receptor, Serotonin, 5-HT1B; D044346:Receptor, Serotonin, 5-HT1D; D011985:Receptors, Serotonin / Q000096:biosynthesis* / Q000235:genetics; D012701:Serotonin / Q000494:pharmacology*; D014661:Vasoconstriction / Q000187:drug effects*
D012333:RNA, Messenger; D044302:Receptor, Serotonin, 5-HT1B; D044346:Receptor, Serotonin, 5-HT1D; D011985:Receptors, Serotonin; D012701:Serotonin; D016686:Monocrotaline