Substance P induces brief, localized increase in [Ca2+]i in dorsal horn neurons.
We determined the spatial and temporal dynamics of the increase in intracellular Ca2+ levels [Ca2+]i produced by substance P (SP) in dorsal horn neurons. A microinjection technique was used to apply minute amounts of SP to small areas of cultured neurons loaded with the Ca2+ indicator fura-2. Five successive applications of SP to the soma produced short-lasting (< 50 s) increases in [Ca2+]i that became gradually smaller, indicating receptor desensitization. Focal application of SP to a distal locus in a neurite produced a brief (12 s) increase in [Ca2+]i that travelled down the dendrite but did not spread into cell soma. Prolonged application of SP to these neurons caused the appearance of varicosities in their dendrites.
Marvizón
J C
JC
Digestive Diseases Research Center, Department of Medicine, University of California, Los Angeles 90095, USA.
Eskandari
S
S
Ennes
H S
HS
Mayer
E A
EA
D000818:Animals; D002118:Calcium / Q000032:analysis / Q000378:metabolism*; D002478:Cells, Cultured; D003712:Dendrites / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D005456:Fluorescent Dyes; D016257:Fura-2; D018698:Glutamic Acid / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D010146:Pain / Q000378:metabolism; D018040:Receptors, Neurokinin-1 / Q000378:metabolism; D013116:Spinal Cord / Q000166:cytology*; D013373:Substance P / Q000494:pharmacology*
D005456:Fluorescent Dyes; D018040:Receptors, Neurokinin-1; D013373:Substance P; D018698:Glutamic Acid; D002118:Calcium; D016257:Fura-2