Showing papers by "Billy R. Martin published in 1984"
Journal Article•
TL;DR: The (-)-isomers of mu agonist/antagonists and kappa agonists competed poorly, or not at all, for the (+)-[3H]NANM site whereas phencyclidine and related compounds exhibited a low affinity for this site.
Abstract: (+)- and (-)-[3H]-N-allylnormetazocine (NANM) were synthesized and evaluated for binding to mouse brain membranes. Scatchard analysis of the saturable binding of (-)-[3H]NANM suggested a single class of binding sites with an apparent KD of 2.1 nM and an estimated maximum binding of 197 fmol/mg of protein. Increasing the concentration of Na+, K+, Mn++ or Ca++ decreased (-)-[3H]NANM specific binding. (-)-[3H]NANM apparently binds to the mu opiate receptor in that (-)-isomers, but not the (+)-isomers, of N-cis-3-chloroallylnormetazocine, N-propynylnormetazocine, pentazocine, cyclazocine, naloxone, phenazocine and morphine competed for binding. (-)-Isomers of ethylketocyclazocine, ketocyclazocine and NIH 9101 also displaced (-)-[3H]NANM binding which suggested kappa activity in addition to mu activity. Phencyclidine and its analogs did not bind to the (-)-[3H]NANM site. Scatchard analysis of saturable binding of (+)-[3H]NANM also revealed a homogeneous population of binding sites with apparent KD of 12 nM and an estimated maximum binding of 360 fmol/mg of protein. This binding site was unaffected by increasing concentrations of Na+ and K+, but binding was decreased by high concentrations of Mn++ and Ca++. The (+)-isomers of the benzomorphans N-cis-3-chloroallylnormetazocine, phenazocine, pentazocine and cyclazocine effectively displaced (+)-[3H]NANM binding. In addition, the (+)-isomers of ketocyclazocine and ethylketocyclazocine, as well as dextrorphan, a (+)-morphinan, bind to the (+)-[3H]NANM site. The (-)-isomers of mu agonist/antagonists and kappa agonists competed poorly, or not at all, for the (+)-[3H]NANM site whereas phencyclidine and related compounds exhibited a low affinity for this site.(ABSTRACT TRUNCATED AT 250 WORDS)
73 citations
TL;DR: The pharmacological potency of R- and S-3'-hydroxy-delta 9-tetrahydrocannabinol (THC) was compared and the difference in potency of these isomers suggests that the conformation of the side chain is critical for behavioral activity.
Abstract: The pharmacological potency of R- and S-3′-hydroxy-Δ 9 -tetrahydrocannabinol (THC) was compared to that of Δ 9 -THC as well as R/S-3′-OH-Δ 9 -THC. The S-isomer was found to be considerably more potent than the R-isomer in producing hypoactivity in mice, static-ataxia in dogs, and in generalization testing in rats trained to discriminate Δ 9 -THC from vehicle. S-3′-OH-Δ 9 -THC was more active than Δ 9 -THC in these tests which means that Δ 9 -THC may be either activated or inactivated in vivo depending upon which metabolite is formed. The difference in potency of these isomers suggests that the conformation of the side chain is critical for behavioral activity. The R and S isomers were found to be equally active in producing hypothermia in mice which is in contrast to the behavioral effects.
24 citations
TL;DR: It appears that dispositional factors are involved in the development of tolerance of mice to the disruptive effects of PCP on DRL performance.
Abstract: Mice trained on a differential reinforcement of low rate 10-sec schedule (DRL 10) were treated daily with either IP saline or 10 mg/kg of phencyclidine hydrochloride (PCP). After 21 consecutive days of treatment, dose-effect determinations for PCP were obtained in both groups. Chronic treatment with PCP resulted in approximately 1.5-fold development of tolerance to the PCP-induced reduction of reinforcement rate. Following completion of the dose-effect determinations, the mice were treated for an additional 13 days with either saline or PCP (10 mg/kg, IP). On the fourteenth day, the biodisposition of 3H-PCP-HCl (10 mg/kg, IP) was studied in both groups. The ratio of the brain levels of PCP in the saline-trained animals to that in the PCP-trained animals was 1.3 to 1 which accounted in large part for the development of tolerance. It appears that dispositional factors are involved in the development of tolerance of mice to the disruptive effects of PCP on DRL performance.
10 citations
TL;DR: It is concluded that the addition of T to P increases the mu-like subjective effects of P and this effect may be due to enhanced affinity of P for themu-receptor.
Abstract: Abuse of the combination of pentazocine (P) and tripelennamine (T) reputedly produces an opiate-like euphoria not obtainable from either drug alone. To determine if this effect is related to interactions at the behavioral or receptor levels we tested this combination in rats trained to discriminate morphine from saline and in mu-receptor binding assays. Displacement of 3H-DHM was compared in morphine-naive, dependent and withdrawn states to determine the importance of prior morphine exposure. The morphine training cue (3 mg/kg) generalized to P but not to T. Combinations of T (0.3 and 1.0 mg/kg) with "no effect" doses of P (1 and 3 mg/kg) resulted in greater than additive increases in morphine-like responding. 3H-DHM was displaced by P but not T in naive, dependent and withdrawn states. Specific dose combinations of T (1 nM) with P (1 nM, 10 nM, 100 nM) resulted in enhanced displacement of 3H-DHM and was not related to prior morphine exposure. We conclude that the addition of T to P increases the mu-like subjective effects of P and this effect may be due to enhanced affinity of P for the mu-receptor.
9 citations
01 Jan 1984
8 citations
TL;DR: Biological activity indicated that a methyl group at the C-9 position is, thus far, optimum for producing hypoactivity and hypothermia in mice.
Abstract: Several 9-substituted delta 8-tetrahydrocannabinol (delta 8-THC) analogues were synthesized and evaluated for biological activity in mice. Compounds with phenyl (2b) and butyl (2c) substituents were prepared by the addition of phenyllithium and n-butyllithium, respectively, to (-)-9-nor-9-oxohexahydrocannabinol (1), followed by dehydration, whereas, isopropyl (2d), PhCH2 (2e), and Ph(CH2)2 (2f) derivatives were synthesized via the Grignard reaction with subsequent dehydration. Compounds with C2H5CH(OH) (2g) and CH3CH(OH) (2h) substituents at C-9 were prepared from (-)-9-nor-9-formyl-delta 8-tetrahydrocannabinol acetate (3) by the reaction of ethyl and methyl Grignard reagents, respectively. Biological activity indicated that a methyl group at the C-9 position is, thus far, optimum for producing hypoactivity and hypothermia in mice. In addition, hydroxyethyl substitution at position 9 reduced and antinociceptive activity of delta 8-THC, in contrast to the increased activity reported for hydroxymethyl substitution.
4 citations
TL;DR: The weak nature of the binding to serum proteins coupled with the relatively high capacity of binding probably account for the failure of other drugs to compete for PCP binding.
2 citations