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. Author manuscript; available in PMC: 2012 Oct 15.
Published in final edited form as: J Neurosci Methods. 2011 Aug 12;201(2):390–398. doi: 10.1016/j.jneumeth.2011.08.011

Fig. 5.

Fig. 5

Effect of intrathecal morphine expressed as current vocalization threshold percent changes from baseline at 1 (Panel A) and 3 h (Panel B) in response to 5, 250, and 2000 Hz sine-wave stimulation. * represents significant (p < 0.05) percent changes from baseline for 5 Hz stimulation, † (p < 0.05) for 250 Hz, and ‡ (p < 0.05) for 2000 Hz. Open and filled symbols represent least square means current vocalization threshold percent changes from baseline for male and female mice combined (as there was no significant effect of sex) and bars represent the standard error for 5, 250, and 2000 Hz. With increasing doses of morphine, percent changes in current vocalization threshold increased and were significantly greater for 5 Hz compared with 250 and 2000 Hz (Panel A). Current vocalization threshold percent changes from baseline at 1 h (Panel A) were significantly ordered: 5 Hz > 250 Hz (p < 0.0001) and 250 Hz > 2000 Hz (p = 0.0002). The curves represent polynomial smooth regression lines for 5, 250, and 2000 Hz frequencies stimulation as indicated in the legend. Data were modeled using repeated measures to compare the effect of increasing doses of morphine among the 3 frequencies at different doses.