Character of the gastric and duodenal electrical activity after blocking of the adrenoreactive structures

Experiments are carried out on six dogs with chronically implanted electrodes in the gastric wall and in the duodenum. The electrical activity of the stomach (EGMG) and of the duodenum (EEG) is recorded. The myoelectrical complex of the stomach consists of four phases. The first phase records only slow potentials and lasts 40--60 min. The appearance of spike activity in the duodenum is always preceded by EGMG activation. Intravenous injection of the specific blocker of the alpha-adrenergic structures (phentolamine -- 1 mg/kg) leads to the appearance of spike activity in EGMG and EEG. 50--60 per cent of the slow waves being accompanied by spike potentials. At the same time the frequency of the slow potentials from EGMG is also decreased. Application of beta-adrenoblocker (propranolol -- 2 mg/kg) does not change subatantially EGMG and EEG. Simultaneous administration of alpha- and beta-adrenoblockers prolongs spiking time in the stomach and duodenum (spike potentials are recorded for 120--180 min, duration in the background 40--50 min). The influence of the interactions of cholinergic and adrenergic structures on the character of EGMG and EEG is discussed.