[Nitric oxide donors and their potentiating effects after botulinum toxin application for treatment of chronic anal fissure].

Pharmacological sphincterotomy with the use of botulinum toxin (BT) that inhibits acetylcholine secretion from neural endings in the motor plate or of nitric oxide (NO) donors should be a method applied earlier than surgical treatment due to its safety. BT mechanism of action on internal anal sphincter is not yet fully understood similarly to the effect of loosening of this sphincter under influence of NO donors applied after BT. Likewise paradoxical vasoconstrictive reaction on acetylcholine in the muscular layer of coronary arteries and decrease of tonic, vasodilative action of NO on the vessels may be observed in the patients with arterial hypertension. However, the muscle tissue of coronary arteries maintains the right dilative reaction on the endothelium independent NO donors. Local application of nitroglycerin is very safe and can be used by physicians in general practice for chronic anal fissure.