GABAA receptor ligands like taurine or responses to other GABAA receptor modulators. Indeed, extrasynaptic receptors involved in tonic inhibition have recently been shown to be sensitive to low concentrations of taurine (Jia et al. 2008a). However, sP and sNP rats do not differ in their sedative-hypnotic responses to other benzo-diazepines and barbiturates (Colombo et al. 2000), but sP rats are more sensitive to the sedative-hypnotic effects of γ-hydroxybutyric acid (Colombo et al. 1998). It is possible that neuroactive steroids may also be involved in innate responses in these animals. 3α,5α-THP and 3α,5α-THDOC are increased in sP vs. sNP rats (Barbaccia et al. 1999). In other selectively bred animals, withdrawal seizure-prone mice are not only found to be more sensitive to the anxiolytic effects of ethanol than withdrawal seizure-resistant mice but they are also more sensitive to the anxiolytic effects of pentobarbital (Atkins et al. 2000). In other studies, FAST & SLOW mice, selectively bred for differences in locomotor stimulatory effects of ethanol, also differ in responses to the convulsant effects of GABAA receptor modulators, and to the locomotor-stimulant effects of benzodiazepines (Shen et al. 1998). Aside from selectively bred animals, inbred strains of mice also suggest a role for GABAA
