Point contacts based on te HTSC YBa2Cu3Ox with low oxygen content (x=6
.75) have been investigated. It was shown that the reversible switchin
g effects between strongly distinct states of a contact, which were re
vealed earlier in point contacts based on similar samples with maximal
oxygen concentration (x almost-equal-to 7.0), take place in this case
as well. It was found that the reason for the switching effects obser
ved is oxygen migration caused by the electric field applied to the co
ntact.