TY - JOUR
T1 - Effects of substance P on identified neurons of the rat dorsal motor nucleus of the vagus
AU - Lewis, M. W.
AU - Travagli, R. A.
PY - 2001
Y1 - 2001
N2 - Previous evidence suggests that substance P (SP) activates subpopulations of neurons within the dorsal motor nucleus of the vagus (DMV). In this study we aimed at identifying these subpopulations in relation to their gastrointestinal projection organs or vagal branches and characterizing pharmacologically the SP response. Using whole cell patch-clamp recordings from identified gastrointestinal-projecting vagal motoneurons, we found that SP induced an inward current in all neuronal groups except for cecum-projecting cells. The lowest percentage of SP-responding neurons was found in fundus-projecting cells, where SP also had a concentration-response curve that was shifted to the left (P < 0.05). Independently from the projections, the SP response was reduced by sendide and MEN 10,376 and mimicked by a combination of [Sar9-Met(O2)11]SP and α-neurokinin. SP and α-neurokinin also increased the frequency, but not the amplitude, of postsynaptic currents. In conclusion, we demonstrated that SP induces both pre- and postsynaptic effects on DMV neurons via activation of neurokinin NK1 and NK2 receptors. The magnitude of the SP response was correlated to the peripheral target organ.
AB - Previous evidence suggests that substance P (SP) activates subpopulations of neurons within the dorsal motor nucleus of the vagus (DMV). In this study we aimed at identifying these subpopulations in relation to their gastrointestinal projection organs or vagal branches and characterizing pharmacologically the SP response. Using whole cell patch-clamp recordings from identified gastrointestinal-projecting vagal motoneurons, we found that SP induced an inward current in all neuronal groups except for cecum-projecting cells. The lowest percentage of SP-responding neurons was found in fundus-projecting cells, where SP also had a concentration-response curve that was shifted to the left (P < 0.05). Independently from the projections, the SP response was reduced by sendide and MEN 10,376 and mimicked by a combination of [Sar9-Met(O2)11]SP and α-neurokinin. SP and α-neurokinin also increased the frequency, but not the amplitude, of postsynaptic currents. In conclusion, we demonstrated that SP induces both pre- and postsynaptic effects on DMV neurons via activation of neurokinin NK1 and NK2 receptors. The magnitude of the SP response was correlated to the peripheral target organ.
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U2 - 10.1152/ajpgi.2001.281.1.g164
DO - 10.1152/ajpgi.2001.281.1.g164
M3 - Article
C2 - 11408269
AN - SCOPUS:0034814694
SN - 0193-1857
VL - 281
SP - G164-G172
JO - American Journal of Physiology - Gastrointestinal and Liver Physiology
JF - American Journal of Physiology - Gastrointestinal and Liver Physiology
IS - 1 44-1
ER -