Inhibition of tongue reflex in rats by tooth pulp stimulation during cerebral ventricle perfusion with (6-11) substance P analogs.

The effect of 12 C-terminal hexapeptide analogs of substance P perfused into the cerebral ventricles on the trigemino-hypoglossal reflex caused by incisor pulp stimulation in rats was investigated. A substitution of the L-isomer by D at position 6, 7, or 8 of the substance P analogs used in this study caused the most pronounced inhibition of the trigemino-hypoglossal reflex. A correlation between the degree of inhibition of the reflex and concentration of the peptide used was observed.