Involvement of adrenal medulla grafts in the open field behavior

Immunohistochemical and behavioral techniques were used to study the effect s of adrenal medulla grafts, implanted in striatum after bilateral kainic a cid (KA) lesions of this structure, on the open field behavior of mice. KA- induced behavioral changes in leaning, grooming and locomotor activity of t he open field test were significantly improved after grafting of the adrena l medulla, and in some respects, fully restored. Immunohistochemical identi fication showed that grafts contained neuron-like cells with a tyrosine hyd roxylase (TH), phenylethanolamine N-methyltransferase, gamma-aminobutyric a cid (GABA), choline acetyltransferase (CkAT), and enkephalin-like immunosta inings. A likely interpretation of this complex pattern of results is that adrenal medullary grafts may restore the deficits of GABAergic neurons whic h in turn reverse the abnormalities in emotionality and locomotion. Neurobi ologically, these behavioral improvements probably involve GABAergic and ca techolaminergic factors, of adrenal medulla grafts, although other neuroact ive substances, such as acetylcholine and enkephalins, cannot be excluded. (C) 2001 Elsevier Science B.V. All rights reserved.