Effects of rolipram on induction of action potential bursts in central snail neurons

• Published in: Experimental neurology 2005-08, Vol.194 (2), p.384-392
• Main Authors: Lin, Chia-Hsien, Lin, Pei-Jung, Chen, Yi-Hung, Lin, Pei-Lin, Chen, I-Ming, Lu, Kuan-Ling, Chang, Yu-Chi, Tsai, Ming-Cheng
• Format: Article
• Language: English
• Subjects: Action Potentials - drug effects; Action Potentials - physiology; Animals; Biological and medical sciences; Bursts of potential; cAMP; Carbazoles - pharmacology; Cell Membrane - drug effects; Cell Membrane - physiology; Central Nervous System - cytology; Central Nervous System - drug effects; Central Nervous System - physiology; Central neuron; Colforsin - pharmacology; Cyclic AMP - metabolism; Electrodiagnosis. Electric activity recording; Estrenes - pharmacology; Fundamental and applied biological sciences. Psychology; Ganglia, Invertebrate - cytology; Ganglia, Invertebrate - drug effects; Ganglia, Invertebrate - physiology; Indoles - pharmacology; Investigative techniques, diagnostic techniques (general aspects); Isolated neuron and nerve. Neuroglia; Magnesium - pharmacology; Medical sciences; Nervous system; Neurons - drug effects; Neurons - physiology; Patch-Clamp Techniques; Phosphodiesterase inhibitors; Phosphodiesterase Inhibitors - pharmacology; Phospholipases - drug effects; Phospholipases - metabolism; Phosphoric Diester Hydrolases - drug effects; Phosphoric Diester Hydrolases - metabolism; Protein kinase; Pyrroles - pharmacology; Pyrrolidinones - pharmacology; Rolipram; Rolipram - pharmacology; Second messenger; Signal Transduction - drug effects; Signal Transduction - physiology; Snail; Snails - cytology; Snails - drug effects; Snails - physiology; Synaptic Transmission - drug effects; Synaptic Transmission - physiology; Vertebrates: nervous system and sense organs
• ISSN: 0014-4886; 1090-2430
• DOI: 10.1016/j.expneurol.2005.02.016

Effects of rolipram, a selective inhibitor of phosphodiesterases (PDE) IV, on induction of action potential bursts were studied pharmacologically on the RP4 central neuron of the giant African snail ( Achatina fulica Ferussac). Oscillations of membrane potential bursts were elicited by rolipram and forskolin. The bursts of potential elicited by rolipram were not inhibited after administration with (a) calcium-free solution, (b) high-magnesium solution (30 mM) or (c) U73122. However, the bursts of potential elicited by rolipram were inhibited by pretreatment with KT-5720 (10 μM). Voltage-clamp studies revealed that rolipram decreased the total inward current and steady-state outward currents of the RP4 neuron. The negative slope resistance (NSR) was not detectable in control or rolipram treated RP4 neurons. TEA elicited action potential bursts and an NSR at membrane potential between −50 mV and −30 mV. It is suggested that the bursts of potential elicited by rolipram were not due to (1) synaptic effects of neurotransmitters; (2) NSR of steady-state I– V curve; (3) phospholipase activity of the neuron. The rolipram-elicited bursts of potential were dependent on the phosphodiesterases inhibitory activity and the cAMP signaling pathway in the neuron.