EN
Four calves were implanted a micro-radio-pressure capsule into their gallbladders in order to measure continuously pressure changes over 3 months. A special programme was designed to compute an electric signal on pressure value expressed in mm Hg. During fasting state, permanent rhythmic pressure changes were superimposed on a cyclic tonic increase in the gallbladder pressure. While rhythmic pressure changes at a frequency of 4,0 ± 0,7 cycles/10 min lasted usually 90,00 ± 7,00 s, the duration of tonic pressure changes was around 24,00 ± 2,90 min being repeated every 95,00 ± 7,00 min. After feeding, the rhythmic pressure changes exhibited a greater amplitude, and occasional long duration of a tonic increase in pressure was prolonged up to 110 min. Caerulein (1 Hg/kg) significantly increased tonic pressure changes. The most abundant response of the gallbladder was seen during the first 20 min of postinjection period, indicating direct actions on its musculature. When injecting pilocarpine (1 mg/kg) of cholinergic potency, the tonic response was more dilated and of a smaller amplitude, but rhythmic pressure changes were distinct. Infusion of 30 μM/min/20 min TCHNa (sodium taurocholate) induced a two phasic increase in gallbladder pressure lasting 35,90 ± 4,70 min. These data suggest that long duration of tonic pressure changes of the gallbladder are controlled by the hormonal, CCK dependent mechanism, but permanent rhythmic pressure changes are influenced by vagal stimulation. It also appears that bile salts can modulate pressure changes of gallbladder, especially trihyd- roksy-derivatives in the form of TCHNa, but the mechanism by which bile salts exert a contractile effect remains to be elucidated.