Modulation of spinal synaptic transmission by beta-melanocyte stimulating hormone (beta-MSH).
Synaptic modulation refers to altered excitability of a synapse by a substance that does not produce a spike potential at the synapse. Available evidence points to the conclusion that beta-melanocyte stimulating hormone (beta-MSH) modulates synaptic transmission through monosynaptic pathways in the cat spinal cord. Earlier evidence is reviewed, and new data are presented. In the first experiments populations of cells contributing to a knee jerk were studied using the Lloyd preparation, and MSH was found to increase the monosynaptic reflex. With intracellular single unit recording techniques, beta-MSH was found to facilitate recovery from synaptic transmission. With extracellular single unit recording techniques and iontophoretic methods for drug application, beta-MSH has been found to increase the probability of generation of single spike potentials by alpha-motoneurons in response to orthodromic stimulation. Administration of beta-MSH did not cause spontaneous discharge of alpha-motoneurons. The physiological and pharmacological importance of synaptic modulation is discussed.
Krivoy
W A
WA
Couch
J R
JR
Stewart
J M
JM
D000818:Animals; D000870:Anterior Horn Cells / Q000187:drug effects; D002415:Cats; D003655:Decerebrate State; D009074:Melanocyte-Stimulating Hormones / Q000494:pharmacology*; D012023:Reflex, Monosynaptic / Q000187:drug effects; D013116:Spinal Cord / Q000187:drug effects*; D013569:Synapses / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects*
D009074:Melanocyte-Stimulating Hormones