A pulsed low-pressure capillary discharge operated in neon, helium and hydrogen gas mixture was used as the source of a high-density plasma with predominantly protons as ions for the measurement of the spectral line profiles of 13 isolated Ne I lines. An electron density of 4.8 × 1022 m−3 with an estimated uncertainty of 10% was determined from the profiles of three He I lines, while an electron temperature of 33 000 K, with an uncertainty of 12%, was measured using the relative intensities of O II impurity lines. The experimental widths of symmetric Ne I profiles are compared with data of two semiclassical calculations using quasi-static and ion impact approximations. The average ratio of measured to theoretical line widths is approximately the same for both theoretical approaches, showing good agreement in either case. This agreement with both theories must be considered, however, to be accidental, for the following reason. In one theory, the electron impact widths are relatively larger with small quasi-static ion contribution, while the other approach produces relatively smaller electron and larger ion impact widths. The asymmetric He I line profiles prove that the semiclassical theoretical approach with quasi-static ion approximation describes better the experimental Stark profiles of He I and Ne I lines. Contrary to the recently reported experimental Ne I line shapes, all studied profiles are symmetric within experimental uncertainty. Possible causes for the line asymmetry and discrepancy of Stark widths with data of this experiment are traced to the plasma source inhomogeneity and plasma diagnostics. Good agreement with several other experiments is detected.