Effects of Repeated Treatment with Midazolam in SHR and SLA16 Rat Strains in the Triple Test

Abstract

We exposed male and female rats of SHR (Spontaneously Hypertensive Rats) and SLA16 (SHR.LEW-Anxrr16) strains, in a non-drugged state, for five consecutive days to the Triple Test (experiment 1); or after repeated treatment with midazolam (MDZ), for four consecutive days. The fifth day was performed without treatment (experiment 2). The first experiment showed that males did not avoid and females increased the exploration of the open arms over the days. In experiment 2, SLA16 from both sexes approached more the open arms than SHR rats. The MDZ anxiolytic-like effect was sustained in both strains and sexes over the days. On the fifth day, SLA16 still approached more the open arms than SHR rats. Data suggest an absence of repeated-trial tolerance to MDZ anxiolytic-like effects. Testing the SHR and SLA16 strains, especially females, could be necessary for the future search for the genes and molecular pathways underlying anxiety/emotionality.

Hunting for Genes Underlying Emotionality in the Laboratory Rat: Maps, Tools and Traps

“…In another study, SHR and SLA16 rats were submitted to the triple test (an apparatus combining the OF, EPM and BWB) for five consecutive days, after repeated treatment with midazolam. It was shown that SLA16 females increased exploration of the open arms of the EPM over days, corroborating the notion that Anxrr16 influences anxiety-like behaviors related to novelty [ 68 ].…”