Honeybee Kenyon cells (KCs) exhibit a tonic GABA receptor current. A: example traces and pooled data (n = 19) showing that picrotoxin (PTX; 50 μM here and subsequently, unless otherwise stated) reduces both the amplitude and variance of KC membrane current (Im), recorded with CsCl-based intracellular solution (CsCl int. soln.; Vh = −65 mV; 5–10 μM mecamylamine in extracellular solution). In this and subsequent figures, example traces show Im immediately before and following at least 5 min of drug application, after any effect has plateaued. B: example traces and pooled data showing the change (Δ) in Im amplitude and variance evoked by bath application of GABA (5 μM, n = 5) and l-glutamate (0.1–0.5 mM, n = 4). The KC tonic current is potentiated by GABA but not by l-glutamate. *P < 0.05, statistical significance.