Table 1.

Effect of 10 μm METH preincubation on synaptosomal membrane potential in rat striatal synaptosomes

	Treatment	Synaptosomal membrane potential ± SEM	[³H]DA uptake ± SEM
In vitro
	Control	62.01 ± 1.98	0.381 ± 0.051
	10 μm METH	57.89 ± 1.29	0.176 ± 0.026^*
In vivo
	Saline	59.43 ± 2.54	0.506 ± 0.023
	METH	59.94 ± 7.19	0.358 ± 0.014^*

For in vitro experiments, synaptosomes were preincubated with 10 μm METH or assay buffer for 30 min at 37°C as described in Materials and Methods, and assayed for the accumulation of [³H]TPP⁺. Values represent means and 1 SEM of determinations from three independent experiments. For in vivo experiments, rats received a single administration of METH (15 mg/kg, s.c.) or saline (1 ml/kg, s.c.) 1 hr before decapitation (n = 6 for each group). Values for synaptosomal membrane potentials represent millivolts; values for [³H]DA uptake represent femtomoles per microgram of protein.
↵* Values different from respective control groups (p ≤ 0.05).