The pharmacologic properties of the tryptolines, hindered analogues of the tryptamines, were studied behaviorally in rats. Following intraventricular injections, it was found that spontaneous motor activity decreased markedly during the initial 25 mins when compared with saline. Since both the tryptolines and tryptamines have been shown to be inhibitors of 5-hydroxytryptamine uptake, it may be possible that these compounds are acting indirectly throught an effect on the serotonergic system.