concentration of acetylcholine at which the reduction in force during dilation of a blood vessel is half the maximum value (EC50) negative logarithm of the molar concentration of acetylcholine at which the reduction in force during dilation of a blood vessel is half the maximum value acetylcholine -Log EC50 A calculated value for the negative logarithm of the molar concentration of acetylcholine (ACh), which acts as a neurotransmitter, at which the dilation of a blood vessel in response to the application of ACh is half maximal. The logarithm of the concentration is the exponent indicating the power to which 10 must be raised to obtain that concentration value. slaulede PMID:32088716 ACh pD2 CMO:0003728 clinical_measurement_ontology acetylcholine -Log half maximal effective concentration (-Log EC50) 2021-06-18T15:57:10Z