Tryptamines behavioral effects

In summary, primary amine and monoalkyl derivatives of tryptamine have not yet been demonstrated to produce hallucinogenic effects in man or to consistently produce profound behavioral effects in animals. Admittedly, relatively few compounds have been examined, and few studies have been conducted. Nevertheless, present evidence suggests that these derivatives, by virtue of their inability to penetrate the blood-brain barrier and/or their rapid metabolism, may not be able to achieve adequate brain levels to elicit effects. In some cases, these factors may lead to masking of potential central effects by peripheral actions of the compounds or their metabolites. 

Martin and co-workers (142,143) have found that, in animals, tryptamine produced many of the physiologic effects characteristic of LSD however, it does not appear to elicit behavioral effects similar to those of LSD. At relatively high doses, 5-methoxytryptamine (24) does produce some behavioral effects in rats (66,242) and in nonhuman primates (101). Vogel (242) has suggested that the disruptive effects of 5-methoxytryptamine might be due to the peripheral actions of this agent. Tryptamine had no effect on acquisition of avoidance behavior, whereas 5-methoxytryptamine slightly decreased such behavior (240). Both tryptamine and 5-methoxytryptamine produced discriminative effects in rats... 

Although the available literature indicates that MAOIs do have agnificant influences on both the metabolism and behavioral effects of DMT, apparently the specific interactions of DMT with 3-carbolines have not been investigated. This apparent oversight is especially remarkable in view of the close structural relationships of tryptamine derivatives and arbolines (see Tables 1 and II), the probable metabolic interconversion of DMT, other tryptamines and /J-carbolines (Barker, Monti 8c Christian 1980 Hsu 8c Mandell 1975), the involvement of both classes of compounds in important neuroregulatory functions such as MAO activity and... 

Marsden, C. A., 1980, Involvement of 5-hydroxytryptamine and dopamine neurons in the behavioral effects of a-methyl tryptamine. Neuropharmacology 19 691-698. 

Trulson, M. E., and Jacobs, B. L. (1979) Effects of 5-methoxy-N.N-dimethyl-tryptamine on behavior and raphe unit activity in freely-moving cats. Eur. J. Pharmacol., 54 43-50. 

Psilocin has also been the object of considerable investigation using animals as subjects. Much of the initial work with psilocin, as well as other 4-hydroxy-tryptamine derivatives with alterations in the side chain and/or terminal amine, was performed at Sandoz Laboratories in Switzerland (29,245). Subsequent investigations have shown that psilocin produces hyperthermia in rabbits (113), induces the head-twitch in mice (43), disrupts acquisition of avoidance behavior in rats (240), increases startle response magnitudes in rats (68), increases limb-flick behavior in cats (120), and produces discriminative stimulus effects in rats similar to those of 5-OMeDMT (59) (93). 

Brimblecombe, R. W. (1967) Hyperthermic effects of some tryptamine derivatives in relation to their behavioral activity. Int. J. Neuropharmacoi, 6 423-429. 

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