Nociceptin Signaling Involves a Calcium-Based Depolarization in Tetrahymena thermophila

Figure 1

Nociceptin is a chemorepellent in Tetrahymena thermophila. Nociceptin (closed circles), nociceptin-NH2 (closed squares), and nociceptin-Arg₁₄Lys₁₅ (closed diamonds) all caused avoidance in Tetrahymena thermophila. The EC₁₀₀ of each compound was correlated with its charge. Nociceptin, which has a net charge of +4, had an EC₁₀₀ of 100 μM. Nociceptin-NH2, which has a net charge of +5, had an EC₁₀₀ of 50 μM. Finally, nociceptin-Arg₁₄Lys₁₅, which had a net charge of +6, had an EC₁₀₀ of 25 μM. 𝑁≥6. 𝑁 represents the number of trials conducted. Each trial consisted of 10 cells, which were individually scored as positive or negative for avoidance.