Extracellular magnesium concentration alters Purkinje cell responsiveness to serotonin and analogues.
Binding studies have shown that divalent cations increase the affinity of 5-hydroxytryptamine 1A (5-HT1A) receptors for ligands. The present study compared the effects of magnesium (Mg2+) at physiologic (1.15 mM) and low (0.56 mM) concentrations on firing rate responses of cerebellar Purkinje cells induced by 5-HT and selective 5-HT1 agonists applied by superfusion or iontophoresis. In low Mg2+ concentrations, the inhibitory actions of 5-HT and 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) but not meta-trifluoromethyl phenyl piperazine (TFMPP) on Purkinje cells were significantly reduced; whereas the excitatory actions to the physiologic agonist 5-HT were enhanced. This report demonstrates a functional role for Mg2+ in the operation of the 5-HT1A receptor located on Purkinje cells.
Darrow
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Department of Physiology, Texas Tech University Health Sciences Center, School of Medicine, Lubbock 79430.
Strahlendorf
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JC
Strahlendorf
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HK
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D000818:Animals; D005110:Extracellular Space / Q000378:metabolism; D007478:Iontophoresis; D008274:Magnesium / Q000494:pharmacology*; D008297:Male; D010879:Piperazines / Q000494:pharmacology*; D011689:Purkinje Cells / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology* / Q000502:physiology; D013764:Tetrahydronaphthalenes / Q000494:pharmacology*
D010879:Piperazines; D011985:Receptors, Serotonin; D013764:Tetrahydronaphthalenes; C018406:1-(3-trifluoromethylphenyl)piperazine; D012701:Serotonin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D008274:Magnesium