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

Fig. 3.

Fig. 3.

Effect of long-term nicotine on UNC-29 receptor abundance. A, Nicotine response and adaptation in animals expressing UNC-29:: GFP chimeric receptors. The levamisole dose–response curves for nicotine-adapted (i.e., cultured overnight on 30 mm nicotine) and naive animals of the strain ZZ2171 (genotype, unc-29(x29); Ex[pmyo-3:: unc-29:: GFP, rol-6d]), which expresses GFP-tagged UNC-29 protein in vulval and body muscles, are shown. Points and error bars represent the mean and SEM of 20 or more trials.Asterisks indicate significantly less egg-laying according to the Mann–Whitney rank-sum test (*p < 0.05; **p < 0.02). Similar results were obtained in animals expressing UNC-29:: GFP under the control of theunc-29 promoter (data not shown). B, Effect of chronic nicotine on vulval muscle UNC-29:: GFP levels. Shown is a digital image of a nicotine-treated adult hermaphrodite expressing UNC- 29:: GFP in the vulval muscles under the control of the unc-29 promoter (indicated by longarrows; the vulva indicated by a shortarrow). An image of a naive animal of the same transgenic line (strain ZZ2001; genotype,unc-29(x29); Ex[punc- 29:: unc-29:: GFP, rol-6d]) is shown for comparison. C, Effect of nicotine on vulval muscle UNC-29 levels inpmyo-3:: unc-29:: GFP animals. Shown are images of nicotine-adapted and naive ZZ2171 hermaphrodites, which express UNC-29:: GFP in the vulval muscles under the control of the muscle myosin promoter pmyo-3.Longarrows indicate vulval muscles; ashortarrow indicates the vulva.D, Time course of loss of UNC-29:: GFP expression in the vulval muscles. ZZ2171 hermaphrodites were placed on seeded NGM containing 30 mm nicotine for the indicated length of time; fluorescence intensity of the vulval muscles is indicated. Verticalbars and error bars indicate the mean and SEM of five or more trials.Asterisks indicate significantly less fluorescence according to the Mann–Whitney rank-sum test (*p < 0.05; **p < 0.001). Lost UNC-29:: GFP fluorescence was 60% recovered after 24 hr on drug-free medium and completely recovered after 36 hr (data not shown).