Effect of saline purgative on frog intestine
Saline purgatives are salts comprising highly charged ions and do not cross cell membranes freely. They remain inside the lumen and retain water through osmotic forces. They increase the volume of the contents of the bowel, stretch the colon, and produce a normal stimulus for contraction of the muscle that leads to defecation. The aim of the present study is to examine the effect of saline purgative on frog intestines.
Reagents: 0.9% to 0.45% of saline (hypotonic), 27% Magnesium Sulphate (hypertonic), Frogs Ringer Solution (isotonic)
Instruments Used: Frog’s board, Pitching needle, dissecting instruments, a needle with thread, and tuberculin syringe with needle.
Pith the frog and place it on a dissecting board. Expose to the abdominal cavity and carefully trace the small intestine. Make the small intestine into three compartments by tying threads of different colors in such a way that no fluid can move from one compartment to the other. Inject 0.2 ml of each hypotonic solution into the first compartment, 0.2ml of the hypertonic solution into the second compartment and 0.2ml of isotonic solution into the third compartment. Wait for 20 minutes and the observations are to be recorded.
Drug Compartment Effect, Hypotonic solution (0.2ml of0.9% of saline) First compartment Shrunken, Hypertonic solution (0.2ml of 27% magnesium sulfate), Second compartment Swollen, Isotonic solution (0.2ml of frogs Ringer solution) Third compartment No change.
The hypotonic solution causes the fluid to move from the lumen into circulation by process of osmosis thereby shrinking the tissue. The hypertonic solution moves the fluid from cells into the lumen and swells the tissue and the isotonic solution did not show any fluid movement across the intestinal membrane.
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