tokens: In order to elucidate the role of the catecholaminergic system in the cataleptogenic effect of delta 9 - tetrahydrocannabinol ( THC ) , the effect of pretreatment with 6 - hydroxydopamine ( 6 - OHDA ) or with desipramine and 6 - OHDA and lesions of the locus coeruleus were investigated in rats .