Expression of 5-HT3 receptors in PC12 cells treated with NGF and 8-Br-cAMP.
1. To determine the functional development of neurons, we applied nerve growth factor (NGF) or 8-bromo-cyclic-adenosine monophosphate (8-Br-cAMP) to PC12 cells and recorded the 5-hydroxytryptamine (5-HT)-induced response by the use of a patch-clamp technique. 2. Cultured PC12 cells expressed 5-HT-sensitive receptors, which are almost absent in untreated cells, in the continuous presence of NGF or 8-Br-cAMP for a period of 10 days. 3. Activation of the receptors by 5-HT produced a transient inward current. In a K(+)-free solution, the reversal potential (E5-HT) of I5-HT was +10.3 mV, and the current-voltage (I-V) relation showed inward rectification at positive potentials. 4. The permeability ratio for monovalent cations was Na+:Li+:K+:Rb+:Cs+ = 1:1.19:0.89:0.94:0.91, indicating that a 5-HT-induced current is passing through the ligand-gated large cation channel. 5. 2-Methyl-5-HT, a specific 5-HT3 agonist, induced a similar inward current, even though the current amplitude was smaller and the activation and inactivation kinetics were slower than those of 5-HT. 6. ICS-205-930, a specific 5-HT3 antagonist, inhibited the 5-HT-induced current in a concentration-dependent manner with a noncompetitive inhibition profile. Spiperone, a 5-HT1 and 5-HT2 families antagonist, and ketanserine, 5-HT2 family antagonist, did not affect the 5-HT-induced response. 7. The time to peak (tp) as well as fast and slow time constants (tau if and tau is) decreased with increasing 5-HT concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
Furukawa
K
K
Department of Neurophysiology, Tohoku University School of Medicine, Sendai, Japan.
Akaike
N
N
Onodera
H
H
Kogure
K
K
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology*; D000818:Animals; D002414:Cations, Monovalent / Q000378:metabolism; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D007211:Indoles / Q000494:pharmacology; D007650:Ketanserin / Q000494:pharmacology; D007700:Kinetics; D008564:Membrane Potentials / Q000187:drug effects; D009414:Nerve Growth Factors / Q000494:pharmacology*; D016716:PC12 Cells; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology; D013134:Spiperone / Q000494:pharmacology; D013997:Time Factors; D000077526:Tropisetron
D002414:Cations, Monovalent; D007211:Indoles; D009414:Nerve Growth Factors; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D015124:8-Bromo Cyclic Adenosine Monophosphate; D012701:Serotonin; D013134:Spiperone; D000077526:Tropisetron; C045918:2-methyl-5-HT; D007650:Ketanserin