Response of splanchnic-driven neurons to substance P and eledoisin-related peptide.
The effects of iontophoretically applied substance P (SP) and eledoisin-related peptide (ERP) on the extracellularly recorded activity of spontaneous or D,L-homocysteic acid (DLH)-driven thoracic (T7-T8) spinal neurons, identified by orthodromic activation by the greater splanchnic nerve, were examined in chloralose/urethane anesthetized cats. Of 24 neurons tested, SP and/or ERP (18-120 nA) produced a weak (ca 30%) excitatory effect on 5 neurons, a weak inhibitory effect on 9 neurons, and no effect on the remaining neurons. When compared to the action of either DLH or GABA, we found both the excitatory and inhibitory effects of SP and/or ERP were delayed and prolonged. These data do not support a role for SP as a major neurotransmitter in spinal circuits in which visceral (splanchnic) afferents participate.
L P
LP
Felpel
R D
RD
Huffman
D000818:Animals; D002415:Cats; D004600:Eledoisin / Q000031:analogs & derivatives* / Q000494:pharmacology; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects; D005260:Female; D007478:Iontophoresis; D008297:Male; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology; D013116:Spinal Cord / Q000502:physiology; D013153:Splanchnic Nerves / Q000187:drug effects / Q000502:physiology*; D013373:Substance P / Q000494:pharmacology*
C019092:substance P analog(eledoisin related peptide); D013373:Substance P; D004600:Eledoisin