Different responses of the blockade of the P2Y1 receptor with BPTU in human and porcine intestinal tissues and in cell cultures

Abstract

Background: Gastrointestinal smooth muscle relaxation is accomplished by activation of P2Y 1 receptors, therefore this receptor plays an important role in regulation of gut motility. Recently, BPTU was developed as a negative allosteric modulator of the P2Y 1 receptor. Accordingly, the aim of this study was to assess the effect of BPTU on purinergic neurotransmission in pig and human gastrointestinal tissues.Methods: Ca 2+ imaging in tSA201 cells that express the human P2Y 1 receptor, organ bath and microelectrodes in tissues were used to evaluate the effects of BPTU on purinergic responses. Key results: BPTU concentration dependently (0.1 and 1 µmol L −1 ) inhibited the rise in intracellular Ca 2+ evoked by ADP in tSA201 cells. In the pig small intestine, 30 µmol L −1 BPTU reduced the fast inhibitory junction potential by 80%. Smooth muscle relaxations induced by electrical field stimulation were reduced both in pig ileum (EC 50 = 6 µmol L −1 ) and colon (EC 50 = 35 µmol L −1 ), but high concentrations of BPTU (up to 100 µmol L −1 ) had no effect on human colonic muscle. MRS2500(1 µmol L −1 ) abolished all responses. Finally, 10 µmol L −1 ADPβS inhibited spontaneous motility and this was partially reversed by 30 µmol L −1 BPTU in pig, but not human colonic tissue and abolished by MRS2500 (1 µmol L −1 ). Conclusions & inferences:BPTU blocks purinergic responses elicited via P2Y 1 receptors in cell cultures and in pig gastrointestinal tissue. However, the concentrations needed are higher in pig tissue compared to cell cultures and BPTU was ineffective in human colonic tissue.

Pharmacological Nature of the Purinergic P2Y Receptor Subtypes That Participate in the Blood Pressure Changes Produced by ADPβS in Rats

“…Altogether, the two main findings of this study using the above P2Y receptor antagonists are: (i) MRS2500, which binds with similar affinities at human and rat P2Y 1 receptors [42],…”

Pharmacological Profile of the Purinergic P2Y Receptors That Modulate, in Response to ADPβS, the Vasodepressor Sensory CGRPergic Outflow in Pithed Rats

“…Nevertheless, these binding data may be transferrable from humans to rodents for several reasons: (i) for ADPβS, the affinity is the same for human and rat P2Y 12 receptors [ 65 , 83 ], but there are only limited differences between rat and human P2Y 13 receptors [ 64 ]; (ii) for ADP, only comparable affinities exist for P2Y 1 and P2Y 13 receptors, which is equipotent on human and rat P2Y 1 receptors [ 66 , 84 ], but it seems slightly more potent on human than on rat P2Y 13 receptors [ 85 ]. The main finding of the present study is the blockade produced by MRS2500 on P2Y 1 receptors ( Figure 3 B and Figure 4 D), which displays a comparable affinity for human and rat P2Y 1 receptors [ 86 ]. To our knowledge, rat binding data do not exist for both PSB0739 and MRS2211; however, for Ticagrelor (an FDA approved P2Y 12 receptor antagonist), there was no difference in affinity for rodent and human P2Y 12 receptors [ 87 ], suggesting a similar pharmacology.…”

E. coli infection disrupts the epithelial barrier and activates intrinsic neurosecretory reflexes in the pig colon

“…We have been able to identify two major pathways, NO and purines acting on P2Y1 receptors as major inhibitory mediators in the porcine colon (Traserra et al, 2021). It is important to notice that despite the clear inhibitory effect of VIP, its role as an inhibitory neurotransmitter is difficult to demonstrate since IJP and corresponding relaxations are blocked with combinations of NOS inhibitors and P2Y1 blockers (Traserra et al, 2021). A functional role of VIP has been reported in the internal anal sphincter of the mouse (Keef et al, 2013).…”

“…Hundreds of papers have evaluated the identities of the inhibitory neurotransmitters using classical NANC conditions. We have been able to identify two major pathways, NO and purines acting on P2Y1 receptors as major inhibitory mediators in the porcine colon (Traserra et al, 2021). It is important to notice that despite the clear inhibitory effect of VIP, its role as an inhibitory neurotransmitter is difficult to demonstrate since IJP and corresponding relaxations are blocked with combinations of NOS inhibitors and P2Y1 blockers (Traserra et al, 2021).…”