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Life Sciences 07/1981; 28(22):2519-28. · 2.53 Impact Factor
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ABSTRACT: The brain and spinal cord of the chronic spinal dog contained higher levels of tryptamine than comparable regions of the intact dog. The most significant brain elevations were found in the cerebellum and mesencephalon. Further, tryptamine in the white matter of the spinal cord above the level of transection was higher than below. These findings have been interpreted as indicating that there are tryptaminergic pathways descending in the white matter of the spinal cord from the mesencephalon, cerebellum and rostral spinal cord. The level of tryptamine below the transection was not different from that found in the intact dog, suggesting that there are not only descending but ascending tryptaminergic pathways and that when the axons are transected. tryptamine accumulates proximal to the level of transection.
Psychopharmacologia 09/1975; 43(2):131-4. · 4.08 Impact Factor
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Journal of Neurochemistry 04/1975; 24(3):523-32. · 4.06 Impact Factor
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Advances in biochemical psychopharmacology 02/1973; 8:503-23.
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Psychopharmacologia 02/1972; 24(3):331-46. · 4.08 Impact Factor
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Archives internationales de pharmacodynamie et de thérapie. 06/1968; 173(1):201-12.
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Journal of Pharmacology and Experimental Therapeutics 05/1968; 160(2):387-96. · 3.83 Impact Factor
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Psychopharmacologia 04/1965; 7(3):159-74. · 4.08 Impact Factor
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ABSTRACT: Actions of the prototypic μ-, κ-, and σ-opiate receptor agonists, morphine (M) ketocyclazocine (K) and SKF-10,047. (S), respectively, were examined and differentiated using the guinea-pig ileum preparation. S, like M and K, depressed the electrically stimulated ileum. Naloxone antagonized the depressant actions of the prototypic drugs with different potencies. PA2 values of naloxone for M, K, and S, respectively, were 8.81, 7.58 and 7.74. Relative cross tolerance of each prototypic drug to normorphine, a comparison standard, was also examined in morphine-pretreated ilea and quantitatively estimated as follows: (1) the median effective dose of each drug and of the standard drug normorphine were determined in the nontolerant ileum (IC50NT) and in ilea with varying degrees of tolerance IC50T); (2) cross-tolerance ratios (IC50T/IC50NT) of each drug and of normorphine were calculated for the varying degrees of tolerance; (3) cross-tolerance ratios of each drug were plotted against those of normorphine, the data were fit by a least squares straight line, and the slope of the line determined as the Relative Cross Tolerance Index (RCTI). RCTI for M was 2.21. K and S, however, had lower RCTI's of 0.44 and 0.64 respectively. In the morphine-pretreated tolerant ilea, slopes of the dose response curves of the prototypic drugs were found to differ: while M and K possessed steep and constant slopes for ilea with different degrees of tolerance, the slopes for S became shallower as ilea became more tolerant to morphine. A maximum ceiling effect of less than 50% depression was obtained for S in the most highly tolerant ilea. The above observations are consistent with possible existence of the three types of hypothesized opiate receptors in the guinea-pig ileum.
Life Sciences.
