Distribution and Function of Platelet-derived Growth Factor Receptor Alpha-positive Cells and Purinergic Neurotransmission in the Human Colon: Is It Different Between the Right and Left Colon?

BACKGROUND/AIMS: Platelet-derived growth factor receptor alpha-positive (PDGFRα(+)) cells function in the purinergic regulation of gastrointestinal motility, and purines are reportedly inhibitory neurotransmitters in the enteric nervous system. We explore the distribution and function of PDGFRα(+) cells related to purinergic inhibitory neurotransmission in human right and left colons. METHODS: Human colonic segments were prepared with mucosa and submucosa intact, and the circular muscle tension and longitudinal muscle tension were recorded. Purinergic neurotransmitters were administered after recording the regular contractions. Immunohistochemistry was performed on the circular muscle layers. Intracellular recording was performed on the colonic muscular layer. SK3, P2RY1, and PDGFR-α mRNA expression was tested by quantitative real-time polymerase chain reaction (qPCR). RESULTS: Adenosine triphosphate (ATP) treatment significantly decreased the frequency and area under the curve (AUC) of the segmental contraction in right and left colons. Beta-nicotinamide adenine dinucleotide (β-NAD) decreased the frequency in the right colon and the amplitude, frequency and AUC in the left colon. Apamin significantly increased frequency and AUC in the left colon, and after apamin pretreatment, ATP and β-NAD did not change segmental contractility. Through intracellular recordings, a resting membrane potential decrease occurred after ATP administration; however, the degree of decrease between the right and left colon was not different. PDGFRα(+) cells were distributed evenly in the circular muscle layers of right and left colons. SK3, P2RY1, and PDGFRα expression was not different between the right and left colon. CONCLUSION: Purines reduce right and left colon contractility similarly, and purinergic inhibitory neurotransmission can be regulated by PDGFRα(+) cells in the human colon.