“…For example, the pharmacological characteristics of GABA receptors associated with pre-and postsynaptic Cl-conductance mechanisms may differ from those mediating enhancement of the binding of benzodiazepines to their receptors (Tallman, Thomas & Gallager, 1978;Karobath, Placheta, Lippitsch & Krogsgaard-Larsen, 1979;Braestrup, Nielsen, Krogsgaard-Larsen & Falch, 1979). They may also differ from autoreceptors thought to be 'Present address: Department of Pharmacology, School of Pharmacy, 29-39 Brunswick Square, London WC 1. 0007-1188/83/010191-16-$01.00 present within the mammalian brain (Mitchell & Martin, 1978;Snodgrass, 1978;Brennan & Cantrill, 1979).…”