Table 1.

Summary of in vitro studies with ziconotide

A. Radioligand binding studies
N-type calcium channels in rat brain membranes or synaptosomes	Saturation binding of 125I-w-MVIIA
	- Kd 1.1 pM (Stoehr and Dooley 1993)
	- Kd 9 pM (Kristipati et al 1994)
	Kinetic analysis of binding of 125I-w-MVIIA
	- Kd 7 pM (Stoehr and Dooley 1993)
	- Kd 18 pM (Kristipati et al 1994)
	Displacement of 125I-w-MVIIA
	- Ki 1 pM (Kristipati et al 1994)
	- IC50 2 pM (Newcomb et al 1995)
	- IC50 7.2 pM (Wang et al 1998)
	- IC50 29 pM (Lewis et al 2000)
	Displacement of 125I-w-GVIA
	- IC50 45 pM (Nielsen et al 1999b)
	- IC50 55 pM (Lewis et al 2000)
B. Electrophysiological studies
Inhibition of native high-voltage-activated calcium currents	Human neuroblastoma, IMR32 cells
	- 42% inhibition of total calcium current at 10 nM (Fox 1995)
	Rat superior cervical ganglion neurons
	- IC50 32 nM, with 90% inhibition (Sanger et al 2000)
	Rat hippocampal neurons
	- 30% inhibition of total calcium current at 3 μM (Wen et al 2005)
Inhibition of recombinant a1B-mediated calcium currents	Human a1B
	- HEK cells, 92% inhibition at 100 nM (Bleakman et al 1995)
	Rat a1B
	- HEK cells, IC50 72 nM (Sanger et al 2000)
	- tsa-201 cells, complete block by 100 nM (Feng et al 2001)
	- Xenopus oocytes, IC50 0.4–11 nM, depending on the a1B splice variant and the absence or presence of the b3 subunit (Lewis et al 2000)
C. Neurotransmitter release studies
Depolarization-evoked norepinephrine release	Rat hippocampus
	- IC50 ~0.5 nM (Newcomb et al 1995)
	- IC50 5.5 nM (Wang et al 1998)
	Rat peripheral sympathetic efferent neurons
	- IC50 1.2 nM (Wang et al 1998)
Depolarization-evoked substance P release	Rat dorsal root ganglion neurons
	- IC50 63 nM (Smith et al 2002)