Preliminary investigation on the effect of aqueous extracts of three
species of kola nut; Cola acuminata (P. Beav), C. nitida
subsp. rubra and C. nitida subsp. alba (Vent), on the rhythmic activity
of mammalian heart and metabolic rate was carried out using male albino
rats, Rattus sp. Low concentrations of kola nut extract
stimulated the heart by increasing rate and force of contraction as
well as metabolic rate. Higher concentrations reduced rate and
amplitude of beat resulting, at still higher concentrations in heart
failure