Experimental study of pre- and postnatal caffeine exposure and its observable effects on selected neurotranmitters and behavioural attributes at puberty

Abstract Caffeine is globally consumed as a stimulant in beverage drinks; it is also ingested in purified forms as power and tablets. Concerns have been raised about the potential consequences of intrauterine and early life caffeine exposure on brain health. This study modeled caffeine exposure during pregnancy and early postanal life until puberty, and the potential consequences. Caffeine powder was dissolved in distilled water. Thirty-two (n = 32) pregnant mice (Mus musculus) were divided into four groups- A, B, C and D. Group A animals served as a control, receiving placebo. Caffeine doses in mg/kg body weight were administered as follows: Group B, 10mg/kg; Group C, 50mg/kg; Group D, 120mg/kg. Prenatal caffeine exposure [phase I] lasted throughout pregnancy. Half the number of offspring were sacrificed at birth; the rest were recruited into phase II and the experiment continued till day 35, marking puberty. Brain samples were processed following sacrifice. γ-aminobutyric acid (GABA), acetylcholine (ACh), and serotonin (5Ht) neurotransmitters were assayed in homogenates to evaluate functional neurochemistry. Anxiety and memory as neurobehavioural attributes were observed using the elevated plus and Barnes’ mazes respectively. Continuous caffeine exposure produced positive effects on short and long-term memory parameters; the pattern interestingly was irregular and appeared more effective with the lowest experimental dose. Anxiety test results showed no attributable significant aberrations. Caffeine exposure persistently altered the neurochemistry of selected neurotransmitters including ACh and 5Ht, including when exposure lasted only during pregnancy. ACh significantly increased in group BC+ to 0.3475µgg-1 relative to control’s 0.2508µgg-1; pre-and continuous postnatal exposure in Group B increased 5Ht to 0.2203 µgg-1 and 0.2213 µgg-1 respectively relative to control’s 0.1863 µgg-1. From the current investigation, caffeine exposure in pregnancy had persistent effects on brain functional attributes including neurotransmitters activities, memory and anxiety. Caffeine in moderate doses affected memory positively but produced negative effects at the higher dosage including increased anxiety tendencies.