Table 1.

Conditions for measuring efavirenz’s ability to displace radioligands specifically bound to the serotonin receptor subtypes. Cloned receptors expressed in cell lines served as the source of all subtypes, except for the 5-HT₄ receptor. The letter(s) in front of the receptor subtype designate the species: h = human, m = mouse, r = rat, gp = guinea pig.

Receptor Subtype	Cell type for expression	Radioligand	Drug for defining non-specific binding	Binding buffer and conditions
h5-HT1A	HEK293	[3H]MPPF	5 μM NAN-190	Buffer A; 90 minutes at 25°C
h5-HT2A	HEK293	[3H]MSP	5 μM mianserin	Buffer A; 90 minutes at 25°C
h5-HT2B	HEK293	[3H]LSD	30 μM mianserin	Buffer C; 90 minutes at 25°C
h5-HT2C	HEK293	[3H]mesulergine	5 μM mianserin	Buffer A; 90 minutes at 25°C
m5-HT3	HEK293	[3H]BRL-43694	10 μM mianserin	Buffer A; 90 minutes at 25°C
gp5-HT4	Striatum	[3H]GR113808	30 μM serotonin	Buffer A; 30 minutes at 25°C
h5-HT5A	CHO-K1	[3H]LSD	100 μM serotonin	Buffer B; 60 minutes at 37°C
r5-HT6	HeLa	[3H]LSD	30 μM chlorpromazine	Buffer C; 60 minutes at 37°C
h5-HT7	CHO	[3H]LSD	10 μM serotonin	Buffer B; 120 minutes at 25°C

Binding Buffer A = 50 mM Tris, pH = 7.4

Binding Buffer B = 10 mM MgSO₄, 0.5 mM EDTA, 50 mM Tris, pH 7.4

Binding Buffer C = 5 mM MgCl₂, 250 μM sodium ascorbate, 50 mM Tris, pH = 7.4

Approximate concentrations of the radioligands used in the displacement assays were 0.5 nM in all cases, except for [³H]GR113808 which was tested at 0.7 nM, [³H]GR113808 which was tested at 1.7 nM, and [³H]LSD which in the case of 5HT_2B was tested at 0.25 nM and in the case of 5HT₇ at 4 nM.