Table 1. Conditions for Measuring Efavirenz Displacement of Radioligands Specifically Bound to Selected Receptor Subtypes.

Receptor	Radioligand	Drug for defining nonspecific binding	Binding buffer	Binding conditions
5-HT1A	[3H]MPPF	5 μM NAN-190	50 mM Tris, pH=7.4 at 25 °C	90 min at 25 °C
5-HT2A	[3H]MSP	5 μM mianserin	50 mM Tris, pH=7.4 at 25 °C	90 min at 25 °C
5-HT2C	[3H]mesulergine	5 μM mianserin	50 mM Tris, pH=7.4 at 25 °C	90 min at 25 °C
D1	[3H]SCH23390	5 μM (+)-butaclamol	50 mM Tris, pH=7.4 at 25 °C	90 min at 25 °C
D2, D3, D4	[3H]MSP	5 μM (+)-butaclamol	50 mM Tris, pH=7.4 at 25 °C	90 min at 25 °C
α2C	[3H]rauwolscine	5 μM risperidone	50 mM Tris, pH=7.4 at 25 °C	90 min at 25 °C
H1	[3H]mepyramine	5 μM cetirizine	50 mM Tris, pH=7.4 at 25 °C	180 min at 25 °C with shaking
Sigma1	[3H]-(+)-pentazocine	5 μM BD1063	50 mM Tris, pH=8.0 at 37 °C	180 min at 37 °C with shaking
VMAT2	[3H]ketanserin	10 μM tetrabenazine	50 mM Tris, 130 mM NaCl, 5 mM KCl, 1 mM MgCl2, 0.5 mM EDTA pH=7.4 at 25 °C	60 min at 25 °C
GHB	[3H]NCS382	1 mM NCS382	50 mM KH2PO4 pH=6.0 at 4 °C	120 min at 4 °C
Opioid (μ, δ, κ)	[3H]naloxone	10 μM naltrexone	50 mM Tris, pH=7.4 at 25 °C	45 min at 25 °C
M1, M4, M5	[3H]Quinuclidinyl benzilate	100 nM atropine	50 mM phosphate, pH=7.4 at 25 °C	60 min at 25 °C
CB1	[3H]CP55,940	10 μM O-2050	50 mM Tris, pH=7.4 at 30 °C, 2.5 mM EDTA 5 mM MgCl2 5 mg/ml fatty acid-free BSA	180 min at 30 °C with shaking

The GHB, opioid, muscarinic, and CB1 receptor assays were performed in rat brain membranes, rather than cloned receptors. Test concentrations for all radioligand were approximately 0.5 nM, except for [³H]quinuclidinyl benzilate, which was tested at 0.15 nM; [³H]-(+)-pentazocine, [³H]naloxone, and [³H]mepyramine, which were tested at a concentration of 1 nM; and [³H]CP55 940 and [³H]ketanserin, which were tested at a concentration of 2 nM.