Table 2

Selective declines in nicotine-evoked dopamine release and [⁸⁶Rb⁺] efflux after MPTP treatment

Region	Nicotine-Stimulated Release/Efflux	Control	MPTP	Percentage of Control
		dpm	dpm
Striatum	[³H]dopamine release^2-a	491 ± 33	269 ± 29***	55 ± 6
	[⁸⁶Rb⁺] efflux^2-b	22.7 ± 1.11	17.8 ± 1.18*	79 ± 5
	[³H]GABA release^2-c	4.20 ± 0.33	4.49 ± 0.18	107 ± 4
Thalamus	[³H]dopamine release^2-a	N.A.	N.A.	N.A.
	[⁸⁶Rb⁺] efflux^2-b	47.1 ± 2.98	48.6 ± 1.89	104 ± 4
	[³H]GABA release^C	2.62 ± 0.27	2.38 ± 0.11	91 ± 4

Nicotine-evoked dopamine release, [⁸⁶Rb⁺] efflux, and [³H]GABA release from synaptosomes was performed as described. A comparison of functional changes in striatum and thalamus in control and MPTP-treated mice showed that there were significant declines in nicotine-evoked [³H]dopamine release and [⁸⁶Rb⁺] efflux in the striatum but not the thalamus, with no change in [³H]GABA release in either region. Dopamine transporter levels in the striatum of MPTP-treated mice were 38 ± 3% (n = 6) of control. Each value represents the mean ± S.E.M. of five to six animals.

N.A., not assayed.
2-150 P < 0.05; ***P < 0.001 compared with control.
↵2-a By 10 μ M nicotine/μ g of synaptosomal protein.
↵2-b By 10 μ M nicotine/dpm in baseline.
↵2-c By 30 μM nicotine/dpm in baseline.