Sungzong Kang

Behavioral observations on compounds found in nutmeg

Myristicin and elemicin impaired the rope climbing and bar-pressing performance of rats and in mice caused catatonia and decreased motor activity. As measured in rope climbing performance, rats developed tolerance to both myristicin and elemicin. There was cross-tolerance between myristicin and elemicin; neither showed cross-tolerance with either Δ9-THC or mescaline. The activity of myristicin and elemicin and the inactivity of other nutmeg compounds (safrole, eugenol, isoeugenol, methylisoeugenol) were not reflected in the energies of the highest occupied molecular orbital. These quantum chemical calculations also imply that the nutmeg compounds are not especially good electron donors.

MOLECULAR DETERMINANTS FOR INTERACTION WITH THE LSD RECEPTOR: BIOLOGICAL STUDIES AND QUANTUM CHEMICAL ANALYSIS

SUMMARY 1 Potencies of a series of tryptamines were measured in three different systems: contraction of the fundus of the rat stomach; inhibition of binding of D-LSD by rat brain membranes; inhibition of uptake of 5-HT by crude rat-synaptosomes. 2 The potencies in contracting the stomach correlated (r=0.94) with potencies in inhibiting D-LSD binding by brain membranes. 3 The potencies correlated with frontier electron densities on the indole ring: Nl, C3, C4, and C5. 4 These positions correspond to the sites at which the density of the highest occupied molecular orbital is localized on 5-HT. 5 Results from ab-initio molecular orbital calculations were used to define reactivity indices for tryptamines: electrostatic interaction potentials and maps of susceptibility to polarization. 6 These indices showed the importance of C4-C5 and the bridge (i.e., C8-C9) regions in polarization complexes such as postulated for interaction with the receptor. 7 From the electrostatic potential maps, force vectors were derived indicating the preferred orientation of the indole ring with another molecule such as a receptor. 8 The vector of the most potent compound, 5-HT, was shown to be perpendicular to that of the least potent compound, 6-HT. The biological consequences of this difference in orientation are discussed. 9 The reactivity indices were tested by calculating the interaction of tryptamines with positive species (e.g., a proton) at various atoms in the indole ring. 10 The resulting interaction energies support the validity of using electrostatic interaction potentials as reactivity indices. 11 The indole nitrogen and carbon atoms respond to the interaction with a proton in a markedly different way. Carbon atoms accumulate the charge, the nitrogen atom transfers it to its neighboring atoms. This charge transduction by nitrogen activates the neighboring atoms for polarization interaction. 12 The interaction of 5-HT as an electron donor with imidazolium as an electron acceptor was studied (in different geometries) as a model of the interaction of tryptamines with receptor sites. 13 The results supported the use of force vectors as criteria for the orientation of reacting molecules in polarization complexes. 14 The charge redistribution resulting from the 5-HT interaction with imidazolium showed that charge transduction occurs when a positive site on imidazolium interacts with the indole nitrogen. This transduction strengthens the complex and could help to explain the importance of nitrogen in activity.