Legend: γ: single-channel conductance; homo: homozygous condition; hetero: heterozygous condition; : current measured in the presence of saturating agonist concentrations; nd: not determined; : permeability to Ca2+; : monoexponential time constant of desensitization; ↑: increase; (↑): small increase; ↑↑: strong increase; ↓: decrease; (↓): small decrease; ↓ ↓: strong decrease. *A. Becchetti and C. Di Resta, unpublished results.