[The excitatory effects of stimulating the presynaptic beta-adrenoreceptors of the ileum in unanesthetized rabbits].

Experiments were performed on unanaesthetized rabbits. It has been shown that beta-adrenergic stimulation by isoprenaline can lead to decreasing as well as increasing of spike activity of the ileum. Pretreatment with propranolol completely prevented both effects of isoprenaline. Administration of isoprenaline both during M-cholinergic and N-cholinergic blockades resulted in decreased spike activity alone. These results suggest that isoprenaline-induced increase in spike activity is mediated by excitatory beta-adrenoceptors localized on the presynaptic cholinergic interneurons of the enteric nervous system.