Journal of Analytical Toxicology
July 1, 2006
James C. Callaway, Charles S. Grob, Dennis J. Mckenna et al.
33 citations
J.C. Callaway, Charles S. Grob, Dennis J. McKenna, David E. Nichols, Alexander Shulgins, Kenneth W. Tupper; A Demand for Clarity Regarding a Case Report on the
Journal of Psychoactive Drugs
June 1, 2005
James C. Callaway
34 citations
Harmine, a major alkaloid in ayahuasca (hoasca), is a selective and reversible inhibitor of the enzyme monoamine oxidase-A (MAO-A). It is also a selective inhibitor of the human cytochrome P450 isozyme 2D6 (CYP 2D6), which metabolizes harmine to a more hydrophilic derivative for eventual excretion. CYP 2D6 exhibits a wide range of polymorphisms in human populations, and variations in this...
Journal of Psychoactive Drugs
June 1, 2005
James C. Callaway
Twenty nine decoctions of Banisteriopsis caapi from four different sources and one specimen of B. caapi paste were analyzed for N,N-dimethyltryptamine (DMT), tetrahydroharmine (THH), harmaline and harmine. Other plants were also used in the preparation of these products, typically Psychotria viridis, which provides DMT. There were considerable variations in alkaloid profiles, both within and...
Journal of Psychoactive Drugs
June 1, 2005
James C. Callaway, Glacus S. Brito, Edison S. Neves
A total of 32 Banisteriopsis caapi samples and 36 samples of Psychotria viridis were carefully collected from different plants on the same day from 22 sites throughout Brazil for phytochemical analyses. A broad range in alkaloid distribution was observed in both sample sets. All B. caapi samples had detectable amounts of harmine, harmaline and tetrahydroharmine (THH), while some samples of P....
Psychopharmacology
February 22, 2001
Jordi Riba, Antoni Rodrı́guez-fornells, Gloria Urbano et al.
302 citations
RationaleAyahuasca is a South American psychoactive beverage that contains the naturally occurring psychedelic agent N,N-dimethyltryptamine (DMT). This "tea" has been used for centuries in religious and medicinal contexts in the rain forest areas of South America and is presently gaining the attention of psychedelic users in North America and Europe.ObjectivesIn the present study, the...
Journal of Ethnopharmacology
June 1, 1999
James C. Callaway, Dennis J. Mckenna, C S Grob et al.
N,N-Dimethyltryptamine (DMT), harmine, harmaline and tetrahydroharmine (THH) are the characteristic alkaloids found in Amazonian sacraments known as hoasca, ayahuasca, and yajè. Such beverages are characterized by the presence of these three harmala alkaloids, where harmine and harmaline reversibly inhibit monoamine oxidase A (MAO-A) while tetrahydroharmine weakly inhibits the uptake of...
Journal of Psychoactive Drugs
December 1, 1998
James C. Callaway, Charles S. Grob
134 citations
The Amazonian psychoactive plant beverage ayahuasca has attracted increasing interest in recent years. Little attention has been given, however, to potentially dangerous interactions with other drugs. In particular, the interaction between the potent monoamine oxidase-inhibiting harmala alkaloids in ayahuasca and the selective serotonin reuptake inhibitor (SSRI) class of antidepressants may...
The Journal of Nervous and Mental Disease
February 1, 1996
Charles S. Grob, Dennis J. Mckenna, James C. Callaway et al.
333 citations
A multinational, collaborative, biomedical investigation of the effects of hoasca (ayahuasca), a potent concoction of plant hallucinogens, was conducted in the Brazilian Amazon during the summer of 1993. This report describes the psychological assessment of 15 long-term members of a syncretic church that utilizes hoasca as a legal, psychoactive sacrament as well as 15 matched controls with no...
Psychopharmacology
November 1, 1994
James C. Callaway, Mauno M. Airaksinen, Dennis J. Mckenna et al.
79 citations
The binding of [3H]citalopram to the platelet 5-hydroxytryptamine (5-HT) transporter was measured in a group of healthy male drinkers of ayahuasca, a psychoactive sacrament indigenous to Amazonia, and a group healthy male controls. An increased number of binding sites (Bmax) in the platelets of ayahuasca drinkers was found, while the dissociation constant (Kd) remained the same for both groups....