Opposite effects of chlordiazepoxide and serotonin receptor antagonists on morphine-induced locomotor stimulation in mice

1982 ◽  
Vol 78 (1) ◽  
pp. 54-57 ◽  
Author(s):  
Mario Sansone
Keyword(s):  
Serotonin Receptor ◽  
Receptor Antagonists ◽  
Locomotor Stimulation ◽  
Serotonin Receptor Antagonists

Serotonin Receptor Antagonists Discriminate Between PKA- and PKC-Mediated Plasticity in Aplysia Sensory Neurons

2006 ◽  
Vol 95 (4) ◽  
pp. 2713-2720 ◽  
Author(s):  
Bogdan Dumitriu ◽  
Jonathan E. Cohen ◽  
Qin Wan ◽  
Andreea M. Negroiu ◽  
Thomas W. Abrams
Keyword(s):  
Sensory Neuron ◽  
Serotonin Receptor ◽  
Marine Invertebrates ◽  
Physiological Saline ◽  
Signaling Cascades ◽  
Evolutionary Divergence ◽  
Receptor Antagonists ◽  
Serotonin Receptor Antagonists ◽  
Kinase C ◽  
Electrophysiological Studies

Highly selective serotonin (5-hydroxytryptamine, 5-HT) receptor antagonists developed for mammals are ineffective in Aplysia due to the evolutionary divergence of neurotransmitter receptors and because the higher ionic strength of physiological saline for marine invertebrates reduces antagonist affinity. It has therefore been difficult to identify antagonists that specifically block individual signaling cascades initiated by 5-HT. We studied two broad-spectrum 5-HT receptor antagonists that have been characterized biochemically in Aplysia CNS: methiothepin and spiperone. Methiothepin is highly effective in inhibiting adenylyl cyclase (AC)-coupled 5-HT receptors in Aplysia. Spiperone, which blocks phospholipase C (PLC)-coupled 5-HT receptors in mammals, does not block AC-coupled 5-HT receptors in Aplysia. In electrophysiological studies, we explored whether methiothepin and spiperone can be used in parallel to distinguish between the AC-cAMP and PLC-protein kinase C (PKC) modulatory cascades that are initiated by 5-HT. 5-HT-induced broadening of the sensory neuron action potential in the presence of tetraethylammonium/nifedipine, which is mediated by modulation of the S-K+ currents, was used an assay for the AC-cAMP cascade. Spike broadening initiated by 5 μM 5-HT was unaffected by 100 μM spiperone, whereas it was effectively blocked by 100 μM methiothepin. Facilitation of highly depressed sensory neuron-to-motor neuron synapses by 5-HT was used as an assay for the PLC-PKC cascade. Spiperone completely blocked facilitation of highly depressed synapses by 5 μM 5-HT. In contrast, methiothepin produced a modest, nonsignificant, reduction in the facilitation of depressed synapses. Interestingly, these experiments revealed that the PLC-PKC cascade undergoes desensitization during exposure to 5-HT.

ChemInform Abstract: Syntheses of O-Methylasparvenone-Derived Serotonin-Receptor Antagonists.

ChemInform ◽  
2010 ◽  
Vol 29 (23) ◽  
pp. no-no
Author(s):  
M. BOES ◽  
H. STADLER ◽  
J. WICHMANN ◽  
F. JENCK ◽  
J. R. MARTIN ◽  
...  
Keyword(s):  
Serotonin Receptor ◽  
Receptor Antagonists ◽  
Serotonin Receptor Antagonists
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