Isolated Rabbit Intestine Learning outcomes Overview for rabbit
Isolated Rabbit Intestine
Learning outcomes: • Overview for rabbit digestive system. • Physiology and pharmacology coordination of rabbit intestine. • A. N. S contribution in intestine function. • Other drugs affecting intestine function.
Physiology of the intestine The small intestine is composed mainly of smooth muscle fibers that are supplied by both divisions of the ANS (Parasympathetic and Sympathetic). Parasympathetic nerve fiber is carried into the cerebrospinal axis via the vagal nerves. Sympathetic fibers to the intestine arise from thoracic-lumbar region.
Parasympathetic stimulation causes increased movement of the intestine. Cholinergic Receptors present in the intestine: • Atropine sensitive receptors • Nicotine sensitive receptors (parasympathetic ganglia). in the wall of the intestine. Sympathetic stimulation leads to inhibition of contractility of the intestine but not the sphincters. Adrenergic Receptors present in the intestine: • Both alpha and beta receptors on the smooth muscle of the intestine leads to intestinal relaxation. • The sphincters contain alpha receptors only and when activated they cause contraction of the sphincters.
Effect of drugs on the isolated rabbit intestine Cholinergic drugs • Parasympathetic ganglia (Nicotine). contraction • Peripheral cholinergic ganglia (physostigmine & pilocarpine) contraction • Peripheral cholinergic blockers (atropine sulphate). relaxation Adrenergic drugs • Adrenergic stimulant (epinephrine) • Adrenergic blockers (presicol) Drugs acting directly on the plain muscles • Barium chloride. • Papaverine. relaxation contraction
Thanx For Your Attention Mostafa sleem Pharmacology & toxicology department SVU
- Slides: 8