Comparative Study Between the Effects of Oral Clonidine and Intravenous Adenosine Triphsophate Infusion on Surgical Stress Response and lsoflurane Requirement

Abstract

Adenosine is a purine nucleotide, having effects on the physiology and biochemistry of the central nervous system. It decreases or increases cyclic AMP levels in the brain by inhibiting or activating the adenylate cyclase with stimulation of A1 or A2 receptors respectively.

Adenosine reduces CNS norepinephrine concentration, thus it IS a CNS . depressant. A decrease in CNS catecholamines concentration is associated with a reduced minimum alveolar concentration. The CNS stimulatory properties of methylxanthines such as theophylline and caffeine are believed to be mediated by blockade of adenosine receptors.

Another hypothesis said that adenosine and its analogues have also been found to be associated with antinociceptive effects after systemic as well as intrathecal administration. The effect is mediated via adenosine A 1 receptors in dorsal hom of spinal cord, which share in reduced requirements of inhalational anesthetics during surgery.

Clonidine, which Is an a2 agonist, had been used as adjunctive in anesthetic practice. It has been administered as premedicant producing sedation and anxiolysis and reducing _. anesthetic requirements. Also, it possesses a potent analgesic