title: Caffeine modulates P50 auditory sensory gating in healthy subjects.
abstract: The P50 suppression paradigm is an index of sensory gating assumed to reflect an inhibitory process. Adenosine is a neuromodulator with mostly inhibitory activity that is released by physiological stimuli and can be blocked by non-selective adenosine receptor antagonists such as theophylline and caffeine. A previous study showed that a single dose of theophylline decreased P50 suppression in healthy volunteers. Here we investigated the effect of caffeine (0, 100, 200 and 400 mg p.o.) on P50 sensory gating in 24 healthy volunteers (15 habitual caffeine high-users and 9 low-users). The 200 and 400 mg doses reduced P50 gating, whereas 100 mg produced a non-significant effect. The effect of caffeine was independent of gender and habitual caffeine intake. High caffeine users also showed baseline differences, with lower S(2) amplitudes compared to low-users. These results reinforce the participation of adenosine in the modulation of P50 sensory gating and suggest that caffeine ingestion should be controlled for in the P50 sensory gating paradigm.
authors.affiliation: Departamento de Ciências Fisiológicas, Faculdade de Biociências, PUCRS, Porto Alegre, Brazil. ghisolfi@pucrs.br
authors.forename: Eduardo S
authors.initials: ES
authors.lastname: Ghisolfi
authors.forename: Alice
authors.initials: A
authors.lastname: Schuch
authors.forename: Ivo M
authors.initials: IM
authors.lastname: Strimitzer
authors.forename: Gustavo
authors.initials: G
authors.lastname: Luersen
authors.forename: Fabíola F
authors.initials: FF
authors.lastname: Martins
authors.forename: Fernanda L P
authors.initials: FL
authors.lastname: Ramos
authors.forename: Jefferson
authors.initials: J
authors.lastname: Becker
authors.forename: Diogo R
authors.initials: DR
authors.lastname: Lara
mesh_terms: D000241:Adenosine / Q000502:physiology; D000328:Adult; D000704:Analysis of Variance; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004569:Electroencephalography; D004585:Electrooculography; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008297:Male; D018047:Receptors, Purinergic P1 / Q000502:physiology
chemical_list: D000697:Central Nervous System Stimulants; D018047:Receptors, Purinergic P1; D002110:Caffeine; D000241:Adenosine