P2Y₁ and P2Y₂ receptor distribution varies along the human placental vascular tree: role of nucleotides in vascular tone regulation

Abstract

The expression of purinergic P2Y receptors (P2YRs) along the cord, superficial chorionic vessels and cotyledons of the human placenta was analysed and functional assays were performed to determine their vasomotor activity. Immunoblots for the P2Y 1 R and P2Y 2 R revealed a 6-to 8-fold increase in receptor expression from the cord to the chorionic or cotyledon vessels. In the cord and chorionic vessels the receptor distribution was mainly in the smooth muscle, whereas in the cotyledon vessels these receptors were equally distributed between the endothelium and smooth muscle cells. An exception was the P2Y 2 R at the umbilical artery, which was distributed as in the cotyledon. mRNA coding for the P2Y 1 R and P2Y 2 R were detected by RT-PCR and the mRNA coding for the P2Y 4 R, P2Y 6 R and P2Y 11 R was also identified. Application of 2-MeSADP and uridine triphosphate (UTP), preferential P2Y 1 R and P2Y 2 R ligands, respectively, resulted in contraction of isolated rings from umbilical and chorionic vessels.

P2Y1Receptor Activation Elicits Its Partition out of Membrane Rafts and Its Rapid Internalization from Human Blood Vessels: Implications for Receptor Signaling

“…Rings were placed in buffer maintained at 37°C in a double-jacketed 5-ml organ baths gassed with 95% O 2 /5% CO 2 . The composition of the Krebs-Ringer solution used at ASPET Journals on May 9, 2018 molpharm.aspetjournals.org was the same buffer described by Buvinic et al (2006). Isometric muscular tension from the circular layer was recorded by means of a force-displacement transducer connected to a Grass multichannel polygraph (Grass, Quincy, MA).…”

“…Antibodies for the human P2Y 1 R were generated and characterized previously (Buvinic et al, 2006). Antibodies against P2Y 2 R, caveolin 1 and 3, flotillin 1, G␣ q , and ␤-subunit of the Na ϩ /K ϩ ATPase were purchased from Santa Cruz Biotechnology (Santa Cruz, CA).…”

“…This value was used as a standard to normalize vasomotor responses of the several bioassays performed. Once the KCl was washed out, the tissue was rested for 15 to 30 min until the vasomotor activities of nucleotides were examined by following the procedure published previously (Buvinic et al, 2006).…”

“…The finding that ATP, ADP, UTP, and adenosine are released from endothelial cells and platelets by a variety of mechanisms (Kunapuli and Daniel, 1998;Lazarowski et al, 2003) and that nucleotides dilate conductance and microcirculation vessels, lowering blood pressure (Burnstock, 1990;Lewis and Evans, 2000), further substantiated the role of nucleotides in the regulation of vascular tone. In particular, the P2Y 1 receptor (P2Y 1 R) was identified in several vascular territories, including the rat mesenteric bed and human placental vessels, in which assays provided pharmacological evidence that this receptor is coupled to the NO/cGMP pathway (Buvinic et al, 2006). In an effort to ascertain the role of P2YRs in the regulation of the human placentae wall tone, we described that P2Y 1 R and the P2Y 2 R are expressed in the superficial vessels of the human chorionic artery (HCA), in which a gradient of P2YR expression along these vessels and its uneven distribution between the smooth muscles and endothelial cells was established (Buvinic et al, 2006).…”

“…In particular, the P2Y 1 receptor (P2Y 1 R) was identified in several vascular territories, including the rat mesenteric bed and human placental vessels, in which assays provided pharmacological evidence that this receptor is coupled to the NO/cGMP pathway (Buvinic et al, 2006). In an effort to ascertain the role of P2YRs in the regulation of the human placentae wall tone, we described that P2Y 1 R and the P2Y 2 R are expressed in the superficial vessels of the human chorionic artery (HCA), in which a gradient of P2YR expression along these vessels and its uneven distribution between the smooth muscles and endothelial cells was established (Buvinic et al, 2006).…”