Efeito do café e da cafeína na modulação do reflexo mandibular de abertura da boca em ratos anestesiados

Abstract

Coffee is a beverage widely used by the general population, and it has a complex composition with more than 600 constituents. Caffeine, one of coffees many components, acts by producing changes in motor activity. Prior studies have shown that jaw reflexes and activity patterns of the jaw muscles were modulated in the presence of jaw muscle pain. There are no studies comparing the modulatory effects on the jaw reflexes influenced by coffee and caffeine diet. To investigate these effects, eight groups of male rats were fed for approximately during 140 days with different diets: a) group 1: control diet; b) group 2: caffeine diet; c) group 3: coffee diet; d) group 4: control diet plus gavage of distillated water; e) group 5: control diet plus gavage of caffeine solution; f) group 6: control diet plus gavage of coffee solution; g) group 7: control diet plus injection i.v. saline solution ; h) group 8: control diet plus injection i.v. caffeine solution. This study investigated the electromyography responses of the digastric muscle elicited by orofacial electrical stimulation. To evoke the nociceptive jaw opening reflex (JOR), an electrical stimulation of the tongue was conducted. Eight parameters of the JOR were measured and analyzed: 1. amplitude (value of the first peak); 2. latency of the first peak; 3. latency of the begin of contraction; 4. maximum inclination; 5. time of the maximum inclination; 6. duration; 7. energy of the control period; 8. energy of the analysis period. The results suggest that chronic and acute intake of caffeine and coffee do not influence the response of the JOR.