Effects of substance P on neurones in the dorsal horn of the spinal cord of the cat.
The activity of single, physiologically identified neurones has been recorded both extra- and intracellularly in the 6th and 7th lumbar segments of the pentobarbitone-anaesthetized cat. In the majority of dorsal horn neurones studies (laminae 4 and 5 of Rexed) microiontophoretically applied synthetic substance P and the active fragment, substance P (4--11), were found to cause a slow and prolonged increase of the spontaneous firing rate and/or an enhancement of L-glutamate induced activity. Intracellular studies revealed that substance P caused a reversible depolarization of both dorsal horn neurones and motoneurones without a detectable alteration of the membrane resistance, antidromic action potential or postsynaptic potentials. These results are compatible with a possible role of substance P in sensory transmission in the spinal cord of the cat.
D000818:Animals; D002415:Cats; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D005727:Ganglia, Spinal / Q000187:drug effects*; D005971:Glutamates / Q000494:pharmacology; D006614:Hindlimb / Q000294:innervation; D008297:Male; D008465:Mechanoreceptors / Q000187:drug effects; D009046:Motor Neurons / Q000187:drug effects; D009474:Neurons / Q000187:drug effects; D012684:Sensory Thresholds / Q000187:drug effects; D012867:Skin / Q000294:innervation; D013373:Substance P / Q000494:pharmacology*; D013569:Synapses / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects
D005971:Glutamates; D013373:Substance P