Figure 7. Pharmacological stimulation of sound production by pressure injection of neuroactive substances into the central complex of restrained male Ch. biguttulus.
A: The duration of stridulation stimulated by 10−4 M muscarine (black column) was reversibly reduced by a single injection of the NO donor SNP (10−3 M) to the same site in the central complex. Significant differences (**: p≤0.01; *: p≤0.05) were calculated with respect to the muscarine pulses before SNP application. B: After overnight storage in an unsealed vessel, SNP solution loses its potency to generate NO upon injection into the central complex. Inactivated SNP had no inhibitory effect on muscarine-stimulated stridulation. C: The duration of stridulation stimulated by 10−3 M picrotoxin was unaffected by co-application of SNP (10−3 M) to the same site in the central complex.