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. 2000 Dec 1;20(23):8802–8811. doi: 10.1523/JNEUROSCI.20-23-08802.2000

Fig. 4.

Fig. 4.

Specificity of the long-term effects of nicotine on egg-laying. A, Effect of long-term nicotine on VC–vulval muscle synapses. Shown here is the expression pattern of a synaptic marker (VAMP:: GFP) that illuminates the VC–vulval muscle synapse, in both nicotine-treated (right) and naive (left) adult animals (synapse identified bylongarrows; the vulva identified by ashortarrow). Animals of the strain NM670 (genotype, lin-15(n765); jsIs42x [punc-4:snb-1:: GFP, lin-15(+)]) were cultured on NGM containing 30 mmnicotine overnight, and images were captured as described in Materials and Methods. Naive animals cultured on NGM alone are shown for comparison. B, Effect of chronic levamisole treatment on the levamisole response. Shown is the levamisole dose–response curve of wild-type animals grown in the presence of levamisole; the dose–response curve of naive animals under the same conditions is shown as a control. N2 hermaphrodites were cultured overnight on NGM containing 50 μm levamisole and then assayed individually for egg-laying for 4 hr under the indicated condition as described in Figure 2. Points and error bars indicate the mean and SEM of 18 or more trials. C, Effect of chronic levamisole treatment on UNC-29 receptor abundance. The histogram compares the UNC-29:: GFP fluorescence intensity in the vulval muscles between naive ZZ2171 animals (see Fig. 3) and ZZ2171 animals treated overnight with levamisole (50 μm) or nicotine (30 mm). Verticalbars and error bars indicate the mean and SEM of five or more trials;asterisks indicate a statistically significant difference from naive animals according to the Mann–Whitney rank-sum test (*p < 0.02). D, Effect of nicotine on vulval muscle UNC-29 protein levels in lev-1mutants. Shown are digital images of naive (left) and nicotine-treated (right) lev-1hermaphrodites expressing UNC-29:: GFP in the vulval muscles. Animals of the strain AQ533 (genotype, unc-29(x29); lev-1(e211); Ex [punc-29:: unc-29:: GFP; rol-6d]) were cultured on NGM containing 30 mm nicotine overnight; UNC-29:: GFP fluorescence was measured as described previously (longarrows indicate vulval muscles, ashortarrow indicates the vulva). Average fluorescence intensities were 120 ± 20 (naive) and 0 ± 0 (nicotine-treated); the difference between these values was statistically significant (p < 0.001) according to the Mann–Whitney rank-sum test. Similar effects were seen in lev-8 and lev-9 mutant animals (J. Kim and W. R. Schafer, unpublished observations).