Caffeine and Nutrition: an Overview - Caffeine: Chemistry, Analysis, Function and Effects - page 13

We subjected both well-nourished and early-malnourished adult rats to the
electrophysiological recording of CSD. The application of a small cotton ball
(1-2 mm in diameter) soaked in 2% KCl (approximately 270 mM) for 1 min to
a point of the frontal cortical surface was a very effective stimulus in eliciting
one CSD episode, which propagated and was recorded at two parietal
recording points. During the recording session, we injected intraperitoneally 30
mg kg -1 caffeine and evaluated the effects on CSD propagation by comparing,
in the same animal, the CSD velocities before and after caffeine. The post-
caffeine CSD velocities were comparable to the pre-caffeine values
(Figure 1.6), indicating no significant effect of the acute administration of
this drug on CSD propagation. However, ANOVA confirmed the previously
described (Guedes 2011) significant effect of nutrition, indicating that
malnutrition increased CSD velocities, as compared to the well-nourished
controls (F [2, 31] 5 14.439; P,0.001).

d n 0 t 2 n g | 3

1.6 Concluding Remarks
An imbalance of some nutrients such as proteins in the diet or consumption of
psychostimulant drugs such as caffeine can cause changes in behavioral
parameters such as mood, perception, motivation, and attention, as well as
modifications in brain electrophysiological features like EEG wave patterns
and the brain's susceptibility to generating and propagating epileptic electrical
activity. In this chapter, we described evaluations of the widely accepted idea
that caffeine can influence behavioral and electrophysiological properties in
the brain and extended the discussion to assessment of the interaction between
caffeine and nutritional deficiency. Our recent experimental results (Aguiar
et al 2011), presented and discussed here, constitute some evidence for a novel
impairing behavioral effect of caffeine on the phenomenon designated as LI
(latent inhibition), a process considered to be related to attention. In addition,
we also demonstrated a failure of caffeine to affect the electrophysiological
phenomenon known as CSD (cortical spreading depression). The type of
nutritional imbalance early in life seems to influence the caffeine effect on LI,
as suggested by the differential effects resulting from the two protein-deficient
diets (see Figure 1.4). The mechanism involved in at least some of the caffeine-
induced brain effects is probably the interaction between this drug and
adenosine A 2A and dopamine D 2 receptors (Fredholm et al 1999). In fact,
studies on LI demonstrate that dopaminergic agents can harm attention (Alves
et al 2002; Bakshi et al 1995). Furthermore, caffeine increases rotation
behavior following dopamine receptor activation, and the effects of caffeine on
LI are similar to those of amphetamine (Fredholm et al 1999). Thus, data
collectively support our speculation that caffeine-induced modulation of

dopaminergic receptors is involved, at least in part, in the effects on LI.
By comparing the effect of caffeine on LI and the absence of effect on CSD,
we suggest that the action of caffeine on the brain, by being more selective than
the actions of malnutrition, more effectively influences the dopaminergic