Biosynthesis of prostaglandin D2 by motoneurons and dorsal horn microneurons: a biochemical and high resolution immunocytochemical study in chick spinal cord.
Prostaglandin D2 is one of the major prostanoids formed from [14C]arachidonic acid by the central nervous system. The aim of the present study is to specify the prostaglandin D2 biosynthetic capacity in the chick spinal cord and to identify the cell type involved in this synthesis. A highly specific and sensitive enzyme immunoassay allowed us to demonstrate that the amount of newly formed prostaglandin D2 increases proportionally with the concentration of free arachidonic acid of either exogenous or endogenous origin and reaches concentration values ranging from 10(-9) to 10(-6) M. The sites of prostaglandin D2 synthesis were localized in Vibratome sections of spinal cord after incubation with antibodies raised against glutathione-independent prostaglandin D synthase; controls were performed with anti-glutathione-dependent prostaglandin D synthase antibodies and non-immune rabbit or goat serum. After immunoprocessing, electron microscope examination revealed that the specific immunoreactivity was confined to small neurons of laminae II and III in the dorsal horn and to motoneurons in the ventral horn of the spinal cord. The immunodeposits were associated with rough endoplasmic reticulum profiles distributed throughout the dorsal horn neurons or restricted to limited subsurface areas of perikarya and dendrites in motoneurons. Since the immunoreactive neurons in the dorsal horn were closely related to blood capillaries, prostaglandin D2 may be suspected to play a role in the regulation of the microcirculation. The accumulation of prostaglandin D synthase in motoneuron areas facing astrocytic membrane stacks suggests that prostaglandin D2 could interact with astrocytic functions.
Vesin
M F
MF
Institut d'Histologie et d'Embryologie, Faculté de Médecine, Lausanne, Switzerland.
Billotte
C
C
Droz
B
B
D000818:Animals; D000831:Animals, Newborn; D001671:Biochemistry / Q000379:methods; D002645:Chickens; D005978:Glutathione / Q000502:physiology; D007150:Immunohistochemistry; D019746:Intramolecular Oxidoreductases; D007535:Isomerases / Q000378:metabolism; D054834:Lipocalins; D008854:Microscopy, Electron; D009046:Motor Neurons / Q000378:metabolism* / Q000648:ultrastructure; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D015230:Prostaglandin D2 / Q000096:biosynthesis*; D011817:Rabbits; D013116:Spinal Cord / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D014018:Tissue Distribution
D054834:Lipocalins; D007535:Isomerases; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase; D005978:Glutathione; D015230:Prostaglandin D2