Influence of prenatal d-amphetamine administration on development and behavior of rats.

Beginning on the fifth day of gestation, rats were administered 1 or 3 mg/kg of $\text{d}$-amphetamine sulfate s.c. twice daily until term. The administration of $\text{d}$-amphetamine caused a dose-related increase in pup mortality. However, the increase in pup death could not be correlated with any gross pathological signs. The surviving 3 mg/kg amphetamine pups were analyzed for changes in motor behavior and brain biogenic amine levels. It was found that the amphetamine offspring showed a marked reduction in the ability to habituate to new surroundings, and this effect persisted for at least three months after birth. On day 35, brain levels of norepinephrine in the “amphetamine” offspring were decreased 21 percent. On day 84, in the “amphetamine offspring,” norepinephrine levels were reduced 18 percent in both the diencephalon and brainstem; dopamine levels were reduced 21 percent in the brainstem compared to control offspring.     

Effects of narcotic antagonists on fluid intake in the rat

The fluid intake (sweetened Enfamil) of rats that had been deprived of food and water for 24 hours was measured following the subcutaneous administration of eight narcotic antagonists and agonists and $\text{d}$-amphetamine. Drugs were tested over at least a 30-fold range of doses. Fluid intake was depressed by the highest dose of each drug, but only the narcotic antagonists naloxone, naltrexone and nalorphine produced dose-related decreases in fluid intake that were not associated with gross disturbances of behavior. The anorexigenic activity of these drugs in the rat does not appear to be related to the drugs' narcotic antagonist properties.     

Complete,reversible, drug-specific tolerance to stimulation of locomotor activity by caffeine

The development of tolerance to caffeine-induced stimulation of locomotor activity was evaluated in rats maintained chronically on average daily doses of 160 mg/kg or more of caffeine by the method of scheduled access to drinking water containing the drug. Dose-response curves were determined for caffeine (6.25–100 mg/kg) and $\text{d}$-amphetamine (0.39–6.4 mg/kg) during chronic drug treatment. In addition, the caffeine curve was redetermined 2–3 weeks after removal of the drug from the drinking water. A control group that had scheduled access to drug-free tap water was also tested. Caffeine produced dose-related increases in the locomotor activity of the controls but failed to modify locomotor activity of the chronic caffeine group. In contrast, $\text{d}$-amphetamine increased locomotor activity of both groups comparably. Spontaneous locomotor of the chronic caffeine group was reduced significantly for 4 days after drug-free tap water was substituted for the caffeine solution. The return of spontaneous locomotor activity to baseline values was associated with restored sensitivity to caffeine-induced stimulation of locomotor activity. Thus, chronic administration of caffeine to rats results in the development of tolerance to caffeine-induced stimulation of locomotor activity that is virtually complete, pharmacologically specific, and fully reversible when drug treatment is stopped. Decreases in spontaneous locomotor activity after abrupt termination of chronic caffeine administration follow a time course consistent with a drug withdrawal syndrome.     

Long-term amphetamine treatment attenuates or reverses the depression of neuronal activity produced by dopamine agonists in the ventral tegmental area

Neuronal activity was recorded from the ventral tegmental area (VTA) of immobilized, locally anesthetized rats on the day immediately following long-term treatment (twice daily for 6 consecutive days) with saline, 1.0 or 5.0 mg/kg $\text{d}$-amphetamine ($\text{d}$-AMPH). Each rat was challenged intravenously with $\text{d}$-AMPH (beginning with 0.0625 mg/kg) or with 0.005 mg/kg apomorphine. Treatment with $\text{d}$-AMPH significantly reduced the ability of this drug to inhibit VTA activity. In fact, nearly half of the neurons in the high-dose treatment group were excited by $\text{d}$-AMPH, whereas only 20% of control neurons showed this response. Moreover, apomorphine routinely accelerated firing rate in the VTA following treatment with 5.0 mg/kg $\text{d}$-AMPH but this response was never observed in control neurons, not even in those that were excited by $\text{d}$-AMPH. Thus, tolerance appears to develop to the ability of dopamine agonists to inhibit VTA activity and this effect may be mediated, at least in part, by a subsensitivity of inhibitory dopamine autoreceptors.     

Effects of LSD and 2-bromo LSD on striatal DOPAC levels.

Administration of d-lysergic acid diethylamide (LSD) and its analogue 2-bromo lysergic acid diethylamide (BOL) resulted in a shortlasting increase of 3,4-dihydroxyphenylacetic acid (DOPAC) levels in the rat striatum. BOL was more potent than LSD in the dose range 0.5–4.0 mg/kg. Since there was a concomitant increase in the striatal $\text{in}$$\text{vivo}$ tyrosine hydroxylation as measured by DOPA accumulation after decarboxylase inhibition, our findings suggest that LSD and BOL increase the impulse flow in the nigro-neostriatal pathway probably by central dopamine (DA) receptor antagonism. However, 4 hrs after LSD the DOPAC level was decreased, while the DOPA accumulation was not. Thus the effect of LSD on the dopaminergic system appears not to be limited to a pure receptor antagonism. The possibility also exists that the effect of LSD on the nigro-neostriatal DA pathway is secondary to its effect on the central 5-hydroxytryptaminergic system.     

LSD and phenithylamine hallucinogens: New structural analogy and implications for receptor geometry

The hallucinogen analog $\text{trans}$-2-(2,5-dimethoxy-4-methylphenyl)-cyclopropylamine (DMCPA) was resolved into its two optical isomers. Examination of selected behavioral profiles in mice and cats clearly showed that the levorotatory isomer of DMCPA possesses stereoselective activity when compared with the dextro isomer. The results parallel those obtained using the isomers of the known hallucinogen, DOM (STP) in the same animal models. Comparison of the optical rotatory dispersion (ORD) curves for the N-(5-bromosalicylidene) derivatives of DMCPA and $\text{trans}$-2-phenylcyclopropylamine (tranylcypromine) of known absolute configuration established the configuration of DMCPA to be (-)-1R,2S. This stereoselective activity and proof of absolute configuration lend strong support to a new model of the hallucinogen receptor. The proposed model suggests possible structural similarities between LSD and phenethylamine hallucinogens.     

Invitro effect of d-lysergic acid diethylamide on immunoglobulin synthesis

Rabbit anti-fluorescyl antibody producing lymphoid cells incubated $\text{in}$$\text{vitro}$ with LSD do not secrete the 7S form of immunoglobulin. The low molecular weight extracellular labeled material shows no measurable anti-fluorescyl antibody activity. Results indicate that during a short incubation period LSD interferes with tryptophan incorporation into antibody protein.     

Interactions of taurine and beta-alanine with central nervous system neurotransmitter receptors

Varying amounts of labeled phenylethylamine (PEA), ptyramine (TRM) and phenylacetic acid (PAAc) were recovered from rabbit brain homogenates at different intervals after the intraventricular (ivn) administration of either labeled L-phenylalanine or PEA. Previous administration of imipramine or amphetamine decreased the recoveries of PEA and PAAc. Imipramine increased the recovery of TRM, which was not affected by amphetamine. The ivn injection of TRM, 2, 5, 10 and 20 min before sacrifice resulted in the recoveries of decreasing amounts of PEA. Pretreatment of the animals with chlorpromazine, haloperidol or smaller doses of Δ⁹-tetrahydrocannabinol (Δ⁹-THC) did not affect PEA recoveries from brain homogenates, whereas amphetamine or larger Δ⁹-THC doses resulted in increased and decreased PEA yields, respectively.These studies further show the existence of an $\text{in}$$\text{vivo}$ brain metabolic pathway linking L-phenylalanine to PEA and TRM. It also shows that these pathways are modified by a number of centrally active drugs.     

Differentiation by cholinergic stimulation of positive inotropic actions mediated via alpha- and beta-adrenoceptors in the rabbit heart.

In the isolated rabbit papillary muscle, experiments were carried out in order to elucidate whether or not cholinergic stimulation produces a differential antagonistic action on the positive inotropic effects mediated $\text{via}$ β- and α-adrenoceptor stimulation. Carbachol (0.1–30 μM) alone scarcely affected the basal tension developed. The postive inotropic effects of phenylephrine (30 μM) in the presence of phentolamine and of isoprenaline, which were mediated $\text{via}$ β-adrenoceptors, were markedly inhibited by carbachol. Carbachol (3 μM) shifted the dose-response curve for isoprenaline in a parallel manner, and that for phenylephrine with phentolamine to the right and downwards. Carbachol administered during induction of the positive inotropic effects $\text{via}$ α-adrenoceptors by phenylephrine (30 μM) with pindolol or by methoxamine failed to inhibit these effects and increased further the tension developed. The dose-response curve for phenylephrine determined in the presence of pindolol was not affected by carbachol. The present results indicate that the cholinergic antagonism of the adrenergic action on the contractility of the mammalian ventricular myocardium is exerted specifically to the β-adrenoceptor-mediated action, but not to the α-adrenoceptor-mediated one.     

Thermogenic and anorectic effects of ephedrine and congeners in mice and rats

(?)-Ephedrine has been shown to increase energy expenditure and cause the loss of body fat in rats and mice. The present study compares the effects of (?)- and (+)-ephedrine, (?)- and (+)- pseudoephedrine, (±)- and (+)-norephedrine and (?)- and (+)-norpseudoephedrine on food intake, energy expenditure and body composition in $\text{ob}$/$\text{ob}$ and normal mice and food intake in rats. The most potent anorectic and thermogenic compounds had the S configuration at the C-2 position but the orders of potencies for the compounds for anorexia and thermogenesis were not identical. The potencies of the compounds in reducing body lipid content correlated better with their thermogenic than their anorectic potencies.     

Stereoselectivity in the metabolism of drobuline (d1-1-(isopropylamino) -4,4-diphenyl-2-butanol) a new anti-arrhythmic agent

The metabolism of drobuline has been examined in the dog, rabbit, rat, guinea pig and hamster. In the dog, unlike the other species, glucuronide conjugation is the major route of metabolism. The structure of the conjugate has been established as an O-glucuronide by isolation using HPLC following by field desorption mass spectral analysis. When the separate $\text{d}$- and $\text{l}$-isomers of drobuline were administered to a series of dogs the $\text{l}$-isomer reached plasma levels approximately three time higher than those of the $\text{d}$-isomer. Deuterium labeled drobuline was synthesized and resolved by multiple crystallizations of the malate salts. Racemic mixtures containing $\text{d}$₆-$\text{d}$ and $\text{h}$₆-$\text{l}$ drobuline and $\text{d}$₆-$\text{l}$ and $\text{h}$₆-$\text{d}$ drobuline were prepared and analyzed by GC-MS as the pentafluoropropionate derivatives. When either racemic mixture was administered to dogs (10 mg/kg, p.o.) the plasma levels of the $\text{l}$-isomer were found to be approximately three times those of the $\text{d}$-isomer. Using these deuterium labeled mixtures the disposition of the two isomers has been examined in the isolated perfused dog liver, in hepatocytes and isolated microsomes. The results indicate that the difference in plasma levels of the $\text{d}$- and $\text{l}$-isomers is not dependent upon stereospecific absorption or excretion but rather it is caused by metabolism of the $\text{d}$-isomer at a faster rate than that of the $\text{l}$-isomer.     

Theoretical studies on the modes of binding of some of the derivatives of d-mannose to concanavalin A

The possible modes of binding for $\text{methyl}\text{-α-}\text{d}\text{-mannopyranoside}$, $\text{methyl}\text{-β-}\text{d}\text{-mannopyranoside}$, $\text{2-O-}\text{methyl}\text{-α-}\text{d}\text{-mannopyranoside}$, $\text{methyl-2-O-methyl}\text{-α-}\text{d}\text{-mannopyranoside}$ and $\text{methyl}\text{-α-}\text{d}\text{-N-}\text{acetylmannosamine}$ to concanavalin A have been investigated using theoretical methods. All these sugars, except $\text{methyl}\text{-α-}\text{d}\text{-N-}\text{acetylmannosamine}$, reach the active site of concanavalin A with a highly restricted number of binding orientations. Present investigations suggest that the failure of $\text{methyl}\text{-α-}\text{d}\text{-N-}\text{acetylmannosamine}$ to bind to concanavalin A is not so much due to steric factors as to repulsive electrostatic interactions. $\text{Methyl}\text{-2-O-}\text{methyl}\text{-α-}\text{d}\text{-mannopyranoside}$ can bind to concanavalin A in one mode whereas the other sugars can bind in more than one mode. The high potency of $\text{methyl}\text{-α-}\text{d}\text{-mannopyranoside}$ over $\text{methyl}\text{-β-}\text{d}\text{-mannopyranoside}$ is mainly due to the possibility of hydrophobic interactions of the α-methoxy group with Leu(99) or Tyr(100) and also due to the possibility of formation of better and more hydrogen bonds with the protein. A comparison of these data with those for the d-glucopyranosides suggests that the change of the hydroxyl at the C-2 atom from equatorial to axial orientation increases the stereochemically allowed region as well as the possible binding modes. From these studies it is also suggested that the overall shape of the oligosaccharides rather than the terminal or internal mannose alone affects the binding potency of saccharides to concanavalin A.     

Evidence that opiate receptors mediate suppression of hypertonic saline-induced drinking in the mouse by narcotic antagonists

The effects of naloxone, its $\text{dextro}$-stereisomer, and five other narcotic antagonists were determined on water intake induced by intracellular dehydration in the mouse. The intraperitoneal administration of a 2M sodium chloride solution served as the model for intracellular dehydration. $\text{1}$-Naloxone (0.01-10 mg/kg) reduced drinking in a dose-dependent fashion with an ED₅₀ of 0.55 mg/kg. In contrast, $\text{d}$-naloxone failed to suppress water consumption at doses up to 10 mg/kg. The other narcotic antagonists tested --- naltrexone, diprenorphine, levallorphan, oxilorphan, and nalorphine --- also produced dose-dependent decreases in water consumption. The order of potency of these narcotic antagonists in suppressing water intake was highly correlated with their orders of potency in other procedures involving the opiate receptor. The stereoselectivity and order of potency suggest that the suppressant effects of the narcotic antagonists on drinking induced by hypertonic saline administration in the mouse are mediated through an opiate receptor-dependent mechanism.     

Assessment of chemically-induced changes in the neuromuscular function of rats using a new recording grip meter

The effects of several psychoactive drugs on the grip strength of rats were evaluated by a new recording grip meter technique that provides graded or continuous data. The same subjects were also tested by an inclined screen procedure, which yields quantal or all-or-none data. The lowest doses (lowest effective dose; LED) required to produce a significant decrease in grip meter scores by chlorpromazine (CPZ), chlordiazepoxide (CDZ), and phenobarbital (PHEN) were 5, 9, and 20 mg/kg respectively. $\text{d}$-Amphetamine (0.5– 8 mg/kg) resulted in a significant, dose-related increase in grip meter scores. The LEDs for CPZ and PHEN using the inclined screen test were 10 and 40 mg/kg, respectively. These values are 2 times the corresponding figures obtained in the grip meter test. The LED for chlordiazepoxide was 9 mg/kg in the inclined screen, which is the same as that in the grip meter test, while $\text{d}$-amphetamine had no effect on neuromuscular function measured by the inclined screen.The results of these experiments indicate that the grip method is a useful technique capable of measuring both increases and decreases in the grip strength of rats. Relative to the inclined screen procedure, which measures a combination of factors, the grip meter technique appears to be a sensitive procedure capable of measuring forelimb grip strength selectively.     

ICI 125,211: a new gastric antisecretory agent acting on histamine H2-receptors.

$\text{In}$$\text{vitro}$, ICI 125,211 competitively antagonized the action of dimaprit on guinea pig atrium with an apparent dissociation constant of 1.5 × 10^?8M (pA₂ = 7.8). $\text{In}$$\text{vivo}$, the histamine dose-response curve in conscious gastric fistula beagles was shifted rightward in parallel without change in the maximal response by intravenous infusions of ICI 125,211 at doses of 0.01 and 0.03 umol/kg/hr (estimated pA₂ = 7.3). Our data show that this new drug is at least 10x more potent than cimetidine as an inhibitor of gastric secretion in the dog. ICI 125,211, which is an orally effective antisecretory agent in man and devoid of antiandrogenic activity, is the most potent selective H₂-blocker described to date.     

Effects of yohimbine and naltrexone in counteraction of the morphine straub tail and the amphetamine-potentiated morphine straub tail in mice

The alpha-adrenergic blocking agent, yohimbine, prevented the production of the morphine Straub tail reaction in mice, although on a mg dose basis it was only about $\text{1}\text{400}$ as potent as the narcotic antagonist naltrexone by subcutaneous injection. Likewise, yohimbine prevented the potentiation of the morphine Straub tail reaction by amphetamine, being about $\text{1}\text{170}$ as active as naltrexone. Preliminary studies with another alpha-adrenergic blocking agent, phentolamine, indicated that it also inhibited the production of the Straub tail reaction by morphine, although it appeared to be somewhat weaker than yohimbine in this respect. These results suggest the involvement of alpha-adrenergic mechanisms in the production of the morphine Straub tail reaction and in the potentiation of the morphine Straub tail reaction by amphetamine.     

Failure of tryptophan load-induced increases in brain serotonin to alter food intake in the rat

The effects on food consumption of 50 and 100 mg/kg $\text{1}$-tryptophan injections, versus control saline treatment, were compared in 24-hour food-deprived rats at two time points in the rats' daily light-dark cycle. No effect of the two tryptophan doses, relative to the saline treatment, on food intake was observed, although tryptophan loading significantly raised brain tryptophan, serotonin, and 5-hydroxyindoleacetic acid levels, in a dose-dependent manner, over baseline concentrations. Implications of these data for serotonergic modulation of food intake regulation are considered.     

The synthesis of methyl 4-O-(4-O-α-d-galactopyranosyl-β-d-galactopyranosyl)-β-d-glucopyranoside: The methyl β-glycoside of the trisaccharide related to Fabry's disease

As part of a program to synthesize the ceramide trisaccharide (1) related to Fabry's disease, methyl 4-O-(4-O-α-$\text{d}$-galactopyranosyl-β-$\text{d}$-galactopyranosyl)-β-$\text{d}$-glucopyranoside (12) was prepared. Methyl β-lactoside (2) was converted into methyl 4-O-(4,6-O-benzylidene-β-$\text{d}$-galactopyranosyl)-β-$\text{d}$-glucopyranoside (4). Methyl 2,3,6-tri-O-benzoyl-4-O-(2,3,6-tri-O-benzoyl-β-$\text{d}$-galactopyranosyl)-β-$\text{d}$-glucopyranoside (7) was synthesized from 4 through the intermediates methyl 2,3,6-tri-O-benzoyl-4-O-(4,6-O-benzylidene-2,3-di-O-benzoyl-β-$\text{d}$-galactopyranosyl)-β-$\text{d}$-glucopyranoside (5) and methyl 2,3,6-tri-O-benzoyl-4-O-(2,3-di-O-benzoyl-β-$\text{d}$-galactopyranosyl)-β-$\text{d}$-glucopyranoside (6). The halide-catalyzed condensation of 7 with 2,3,4,6-tetra-O-benzyl-$\text{d}$-galactopyranosyl bromide (8) gave methyl 2,3,6-tri-O-benzoyl-4-O-[2,3,6-tri-O-benzoyl-4-O-(2,3,4,6-tetra-O-benzyl-α-$\text{d}$-galactopyranosyl)- β-$\text{d}$-galactopyranosyl]-β-$\text{d}$-glucopyranoside (10). Stepwise deprotection of 10 led to 12, the methyl β-glycoside of the trisaccharide related to Fabry's disease.     

Daily rhythms of glycogen synthetase and phosphorylase activities in rat liver: Influences of food and light

In rats fed during the night time (from 8 p.m. to 8 a.m.) the activities of liver glycogen synthetase $\text{I}$ and phosphorylase $\text{a}$ varied rhythmically during a 24 hour period. There was an inverse relationship between their levels; the level of synthetase $\text{I}$ rose to a maximum at around 6 a.m. and that of phosphorylase $\text{a}$ attained the peak value at around 6 p.m. Eye enucleation of rats did not affect significantly the daily rhythms of the enzymes. However, when food was offered only during the day time, the phases of both enzyme rhythms were shifted by about 12 hours. On starvation for 24 hours, the glycogen level was reduced almost to nil, but the daily rhythms of the enzymes were retained. It is thus very likely that the daily variations of the enzyme activities are not merely a passive effect of food intake, and that food can be a synchronizer or zeitgeber which sets up the characteristic rhythms of glycogen metabolism in the liver.