Purinergic neuromuscular transmission is absent in the colon of P2Y1 knocked out mice

Key points Neural-mediated relaxation occurs in the gastrointestinal tract. To accomplish this function, two neurotransmitters, ATP or a related purine and nitric oxide, are released by inhibitory motorneurons. The type of purinergic receptor is still under debate but previous data using a classical pharmacological approach (receptor agonists and antagonists) suggested that P2Y1 receptors are responsible for purinergic neurotransmission in the gastrointestinal tract. In the present study we used a genetically modified mouse in which P2Y1 receptors had been knocked out. P2Y1-deficient mice had functional nitrergic neurotransmission but purinergic neurotransmission was absent. The present work confirms the hypothesis demonstrating that P2Y1 receptors mediate the purinergic component of the smooth muscle relaxation in the gastrointestinal tract.