Etorphine in man. I. Subjective effects and suppression of morphine abstinence

The effects of etorphine, a potent morphine-like drug, were qualitatively and quantitatively compared to those of morphine. In nondependent subjects, etorphine in doses of 0.025, 0.050, and 0.100 mg produced pupillary constriction and morphine-like subjective effects and euphoria. Etorphine was 500 times as potent as morphine, with a very rapid onset and short duration of action. In morphine-dependent subjects, etorphine suppressed abstinence but for a shorter period than morphine. These studies indicate that in man etorphine is a morphine-like drug with a high abuse potential.

Chemical selection of mutants that affect alcohol dehydrogenase in Drosophila. II. Use of 1-pentyne-3-ol

We describe a procedure for the selection of alcohol dehyrogenase negative mutants in Drosophila. The method consists of exposing eggs and larvae to low concentrations of 1-pentyne-3-ol dissolved in the culture medium. Only those flies with greatly reduced levels of alcohol dehydrogenase activity survive. In addition, genotypically negative flies die if their mothers are alcohol dehydrogenase positive. Using this procedure and formaldehyde to generate mutants, we were able to detect seven alcohol dehydrogenase negative mutants out of 350,000 individuals subjected to selection. At least five of the mutants contain small deletions that include the alcohol dehydrogenase locus.

Effects of some aliphatic alcohols on the conductance change caused by a quantum of acetylcholine at the toad end-plate

1. The post-synaptic effects of the aliphatic alcohols, ethanol to hexanol, were investigated at the neuromuscular junctions of toads, with particular emphasis on the effects of ethanol. 2. The alcohols increased the amplitude and duration of miniature end-plate potentials. It is shown that this effect was due to the prolongation of the decay phase of miniature end-plate currents (m.e.p.c.s). There was no effect of alcohols on the growth phase of m.e.p.c.s. 3. The prolonged decay of m.e.p.c.s in ethanol remained exponential and was normally sensitive to membrane potential. Prolonged m.e.p.c.s were associated with an equivalent prolongation of the mean duration of elementary events, as determined from power spectra of acetylcholine noise in 0-5 M ethanol. 4. The relationship betweeen the time constant of decay of m.e.p.c.s (tau) and the concentration of an alcohol of carbon chain length N (C-N) was exponential, conforming to the equation tau equals tau-s exp (B-N-C-N), in which tau-s is the decay time constant in standard solution and B-N is a constant, different for each alcohol. 5. There was also an exponential relationship between B-N and N, which closely followed the relationship between membrane-buffer partition coefficient and carbon chain length for the different alcohols, indicating that the alcohols are active in the lipid phase of the post-synaptic membrane. 6. It is suggested that the alcohols act by causing a change in the dielectric constant of the post-synaptic membrane which forms the environment of the rate-limiting reaction responsible for the decay of the end-plate conductance. On the assumption that this reaction involves dipoles, it is shown that the small changes in dielectric constant, calculated from the partition coefficients of the alcohols and by assuming an initial lipid dielectric constant of 3, would give an exponential relationship between the time constant of decay of m.e.p.c.s and alcohol concentration. 7. The results support the hypothesis that the decay (but not the onset) of acetylcholine-induced conductance changes is rate-limited by a first-order reaction which involves dipoles and occurs in the lipid environment of the post-synaptic membrane.

Utilization of alpha-keto and alpha-hydroxy analogues of valine by the growing rat

When 70-80-g male albino rats eat a diet furnishing daily requirement of valine for optimal growth (70 mumol/g) and all other nutrients ("complete diet"), they gain weight at an average rate of 3.0 g/100 g body wt/day. When valine is removed, they lose weight at an average 2.1 g/100 g body wt/day. The growth retardation is improved or corrected by adding valine to the diet, daily weight gain being proportional to dietary valine content over a range of 0-70 mumol/g. Addition of alpha-ketoisovaleric acid instead of valine to the valine-free diet also improves or corrects the growth failure. Percent efficiency of alpha-ketoisovaleric acid as a substitute for valine was calculated as: 100 x (micromole valine per gram diet required to produce specified growth response)/(micromole alpha-ketoisovaleric acid per gram diet required to produce the same response). Efficiency of the substitution is inversely related to dietary content of the keto analogue, being 80% when diet contains 17.5 mumol/g (molar equivalent of (1/4) the daily requirement of valine), and 37% when diet provides 140 mumol/g (molar equivalent of twice the daily requirement of valine).alpha-Hydroxyisovaleric acid also substitutes for valine. Efficiency of the substitution at the single ration tested, 70 mumol/g diet, is 45%, similar to that for the keto analogue under the same conditions. When [1-(14)C]alpha-ketoisovaleric acid is injected intravenously, 30-80% of the administered radioactivity is exhaled as (14)CO(2) within 24 h. This finding suggests that inefficiency of alpha-ketoisovaleric acid as a substitute for valine results in part from degradation of the keto acid to isobutyric acid by branched chain dehydrogenase-decarboxylase. Oral administration of neomycin, polymyxin, and bacitracin reduces efficiency of alpha-ketoisovaleric acid as a substitute for valine by (1/4)-(1/2). This effect suggests that transamination of the keto acid may be performed in part by gastrointestinal microbes.

Comparative study of the development of alkaline phosphodiesterase I and alkaline phosphatase in mucosa of rat jejunum and ileum

During the early postnatal period phosphodiesterase I is almost equally distributed in the jejunum and the ileum of rat intestine. By the end of the third week after birth the specific activity in the jejunum decreases to about one-half and in the ileum to about one-tenth of the activities found on the ninth day, forming a proximo–distal gradient typical of adult animals. The activity of alkaline phosphomonoesterase in newborns is much lower than that of phosphodiesterase I and increases rapidly the first day. During the second week the specific activity of alkaline phosphatase in the ileum rises to more than double that in the jejunum and the final proximo–distal gradient is established somewhat later. For both enzymes the amount of activity appearing as soluble cytoplasmic material is highest in newborn rats and diminishes as the animals mature. The extractibility of activity from the insoluble microsomal fractions with Triton X-100 follows the same trend. After extraction of the enzymes from microsomes by treatment with tert-amyl alcohol, Triton X-100, or glycerol, most of the phosphodiesterase I activity appears in large complexes of molecular weight of several millions, but after autolysis the complexes break down to molecules of molecular weight close to 150 000 without appreciable loss of activity.