Effects of methylphenidate on the inhibitory postsynaptic potential in rat locus coeruleus neurons.
Effects of methylphenidate (MPH), an agent used clinically for the treatment of children presenting the attention-deficit/hyperactivity disorder (AD/HD), on synaptic transmission in the rat locus coeruleus (LC) were examined by intracellular recording methods. Bath-application of MPH (30 nM-3 microM) increased the amplitude of the inhibitory postsynaptic potential (IPSP), while it did not change the amplitude of the excitatory postsynaptic potential (EPSP). MPH increased the time-to-peak and the half-decay time of the IPSP in LC neurons. MPH increased the amplitude of spontaneous IPSP: individual spontaneous IPSPs merged one into the other so as to produce regular, long-lasting waves of hyperpolarization. Clonidine (10 nM), a selective agonist for alpha 2-adrenoceptors, depressed the IPSP without affecting the EPSP in LC neurons. The results suggest that MPH enhances inhibitory synaptic transmission in the rat LC by depressing the norepinephrine (NE) re-uptake system.
Kuwahata
Takashi
T
Department of Physiology, Kurume University School of Medicine, 67 Asahi-machi, Kurume 830-0011, Japan. akasut@med.kurume-u.ac.jp
Ishimatsu
Masaru
M
Kidani
Yuri
Y
Akasu
Takashi
T
D000818:Animals; D003000:Clonidine / Q000494:pharmacology; D005071:Evoked Potentials / Q000187:drug effects; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D006801:Humans; D066298:In Vitro Techniques; D008125:Locus Coeruleus / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008774:Methylphenidate / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D009435:Synaptic Transmission / Q000187:drug effects
D008774:Methylphenidate; D003000:Clonidine