Expression of type1 and type 4 proteinase-activated receptors (PAR1 and PAR4) in murine uterus

We have shown that peptide ligands of type 1 and type 4 proteinase-activated receptors (PAR(1) and PAR(4)) stimulate contractile activity of isolated uterus rings of adult mice and do not induce contraction of uterus rings from immature mice. Using reverse transcription and polymerase chain reaction (RT-PCR) the presence of PAR(1) and PAR(4) mRNA was detected in uterus of immature, adult, and pregnant mice. It was suggested that the lack of physiological response to PARs ligands in uterus of immature mice could be due to either low level of translation from PARs mRNA or the absence or low activity of some component (s) of signaling system activated by PARs.