Influence of catecholamines on epidermal cell migration during wound closure in adult newts

Following removal of a skin patch from each hind limb of a series of adult newts, the limbs were explanted into small dishes of Holtfreter solution containing various combinations of test drugs. Later, the amount of wound epithelium that formed on each limb was determined using a planimeter on wound tracings obtained with the aid of a drawing tube-equipped microscope. All three (-)-catecholamines tested inhibited migration with the following order of effectiveness: isoproterenol greater than epinephrine greater than norepinephrine. The effect was stereospecific with (-)-isoproterenol clearly more effective than the (+)-isomer. Propranolol, a beta antagonist, blocked the effect of (-)-isoproterenol while the alpha antagonist, phentolamine, was less effective. One hour in (-)-isoproterenol inhibited migration to the same degree as continuous exposure for the 6 hr most experiments were allowed to run. Taken together, the data suggest that catecholamines exert their effect on epidermal cell migration via beta 2 adrenergic receptors on the cell surface, a binding site which implicates cAMP in the chain of events.