DIFFERENT EFFECTS OF THE ATROPINE UPON THE PENDULOUS MOVEMENTS OF THE PROXIMAL AND OF THE DISTAL COLON OF THE RABBIT

Abstract

The influence of the non-selective blocker of the muscarinic receptors, namely of the atropine (1,7 x10-10 - 5x10-7). upon thependulousmovements of the proximal and of the distal colon of the rabbit was studied. In the correct proportion to the concentration the atropine reduces the amplitude of both the proximal (r=0,98; P<0,001) and of the distal colon (r= 0,97; P < 0,001). On the basis of the ED50 values - that amount to 7,7 ± 0,03 x 10-7 M for the proximal colon and 3,5 ± 0,06 x 10-5 M for the distal colon, the atropine recluces for twenty times the amplitude of the pendulousmovements of the rabbit's distal colon. Likewise, it reduces for dozen times the frequency of the pendulous movements of the distal colon (ED50 = 5 ± 0,02 x 10-6M) with respect to the proximal one (ED50 = 4,7 ± 0,06 x I0-5M). The atropine does not change the tone of the proximal colon (average relaxation is 5,47 ± 2,32 %) while it induces the concentrically-dependent relaxation of the distal colon (maximal relaxation amounts to 38.03 + 8,34). The ED50 values for the atropine while affecting the distal colon tone is 1,7 ± 0,03 x 10-6M.

Keywords

• Atropine
• different effects
• pendulous movements
• rabbit's colon