Karen K. Szumlinski
The reason for selecting females was two-fold. 1) female rats typically display augmented behavioural activation to most psychomotor stimulants and we were using locomotor activity as a dependent measure. the activity monitors used have opaque black walls so oral behaviours cannot be monitored; 2)ibogaine pharmacokinetics differ in male and female rats and females typically display augmented ibogaine effects, compared to males. Females are traditionally used in our lab for the latter reason.
I should mention that, for locomotor studies, Sprague-Dawley rats are typically used in our lab and all previous studies of ibogaine's effects on drug-induced locomotor behaviour have used this strain. I opted to use LEH rats in hopes of optimizing the locomotor effects of cocaine, as this strain appears to be more susceptible to the behaviour-activating effects of stimulants, compared to albino strains. This option may have back-fired as the possibility exists that our animals failed to develop and expression sensitization because they expressed near maximal levels of locomotion in response to cocaine on injection 1 of chronic treatment (although the short withdrawal period between termination of chronic treatment and test day may also be an important factor contributing to our lack of sensitization). For subsequent studies, I have used female SD rats with a 2 week withdrawal period, have observed sensitization, and replicated and extended past and present findings.