Aminergic influences on intravenous cocaine self-administration by rhesus monkeys

Earlier observations have demonstrated that when allowed limited daily access to cocaine, monkeys self-administer approximately the same amount of cocaine daily. Treatment with neuroleptic agents increases the frequency of this behavior which could be interpreted as resulting from an antagonism of the reinforcing actions of cocaine. The present paper demonstrates that agents known to alter central aminergic systems affect cocaine self-administration. Acute treatment with pargyline (50 and 100 mg/kg) decreased the behavior; DL alpha-methylparatyrosine (50 mg/kg) increased the behavior. Treatment with the peripheral alpha adrenergic blocking agents phentolamine and phenoxybenzamine (0.5 - 8.0 mg/kg) did not significantly alter the behavior. Chronic treatment (5-10 days) with reserpine (0.1 - 1.0 mg/kg) produced an initial increase in self-administration to which tolerance developed. Upon discontinuation of reserpine treatment, cocaine self-administration was decreased below baseline levels. Results tend to implicate either dopamine or norepinephrine as mediators of either cocaine-based reinforcement or of the other effects of cocaine which may regulate the frequency of its administration. Results were discussed in relation to those obtained from clinical studies in which drug effects on amphetamine-induced euphoria were ascertained.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22290/1/0000730.pd

The effects of chlorpromazine on psychomotor stimulant self-administration in the Rhesus monkey

The effects of acute and chronic chlorpromazine treatment on psychomotor stimulant self-administration behavior in the Rhesus monkey were determined. Chlorpromazine treatment significantly increased the frequency of self-administration of cocaine, pipradrol, phenmetrazine, d -amphetamine and methylphenidate. The basis of this effect was thought to either be due to an antagonism of the reinforcing effect of these compounds or an antagonism of those actions of the psychomotor stimulants which may function in limiting their self-administration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46383/1/213_2004_Article_BF00422098.pd

Cholinergic influence on intravenous cocaine self-administration by rhesus monkeys

The effects of intramuscular administration of atropine, methylatropine and physostigmine on intravenous cocaine self-administration in the rhesus monkey were ascertained. Atropine (0.5-2.0 mg/kg) increased cocaine intake, whereas methylatropine, over the same dosage range, produced no change in this behavior. Physostigmine (0.1-0.5 mg/kg) significantly depressed this behavior. The effect of atropine was interpreted as being the results of its central anti-cholinergic action and that of physostigmine, since it was opposite to that of atropine, was attributed to its central cholinergic action. Furthermore it was hypothesized that the effect of these cholinergic interactions on cocaine self-administration resulted from a modulation of the factors which may control self-administration i.e. drug-induced aversiveness or nonspecific behavioral disruption rather than any specific interaction with the neurochemical mechanisms of cocaine mediated reinforcement. The drug effects support the concept of a central cholinergic behavioral inhibitory system which when blocked, e.g., with atropine, results in behavioral activation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33790/1/0000045.pd

Mazindol self-administration in the rhesus monkey

The ability of the intravenous administration of mazindol (SaH 42-548) to act as a reinforcer in monkeys previously conditioned to self-administer cocaine was ascertained. Unit dosages i.e. dosage per injection, of 50 and 100 [mu]g/kg resulted in self-administration rates significantly greater than that which occurred with saline. An inverse relationship existed between unit dosage and frequency of self-administration over the unit dosage range 50-200 [mu]g/kg. The total mazindol dosage self-administration per session was however independent of unit dosage. Approximately 2-3 mg/kg was self-administered by each animal during a 4 hr session at each of the 3 unit dosages. This tends to indicate that the 200 [mu]g/kg unit dosage was also reinforcing even though the self-administration rate was similar to that of saline. This study indicates that mazindol can serve as a reinforcer and that the relationship between total session intake, unit dosage, and self-administration frequency of mazindol are similar to these seen with other reinforcing psychomotor stimulant drugs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/21830/1/0000233.pd

Foreword

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26141/1/0000218.pd

Behavioral effects of thebaine in the rhesus monkey

Three experiments were conducted with rhesus monkeys to assess some behavioral effects of the opium alkaloid, thebaine, in relation to its dependence liability. The concurrent intramuscular administration of naloxone did not antagonize the rate-decreasing effects of thebaine on a fixed-ratio (FR) schedule of food-reinforced responding. Animals trained to self-administer codeine (0.3 mg/kg/inj) on an FR 30 schedule did not self-administer thebaine (0.003-1.0 mg/kg/inj) at rates comparable to those of codeine. Rates were minimally above those of saline at 0.3 mg/kg/inj. Monkeys given 23 hrs/day continuous access to 1.0 mg/kg/inj thebaine did, however, self-administer the drug at rates significantly higher than those maintained by saline, but not as high as those supported by 2.0 mg/kg/inj codeine. Two animals self-administering thebaine did not show any signs of withdrawal when injected with 0.1-1.0 mg/kg of naloxone or when saline was substituted for thebaine. A third monkey showed a severe reaction leading to death following an injection of 1.0 mg/kg naloxone.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24370/1/0000639.pd

Aeroelastic Response and Protection of Space Shuttle External Tank Cable Trays

Sections of the Space Shuttle External Tank Liquid Oxygen (LO2) and Liquid Hydrogen (LH2) cable trays are shielded from potentially damaging airloads with foam Protuberance Aerodynamic Load (PAL) Ramps. Flight standard design LO2 and LH2 cable tray sections were tested with and without PAL Ramp models in the United States Air Force Arnold Engineering Development Center s (AEDC) 16T transonic wind tunnel to obtain experimental data on the aeroelastic stability and response characteristics of the trays and as part of the larger effort to determine whether the PAL ramps can be safely modified or removed. Computational Fluid Dynamic simulations of the full-stack shuttle launch configuration were used to investigate the flow characeristics around and under the cable trays without the protective PAL ramps and to define maximum crossflow Mach numbers and dynamic pressures experienced during launch. These crossflow conditions were used to establish wind tunnel test conditions which also included conservative margins. For all of the conditions and configurations tested, no aeroelastic instabilities or unacceptable dynamic response levels were encountered and no visible structural damage was experienced by any of the tested cable tray sections. Based upon this aeroelastic characterization test, three potentially acceptable alternatives are available for the LO2 cable tray PAL Ramps: Mini-Ramps, Tray Fences, or No Ramps. All configurations were tested to maximum conditions, except the LH2 trays at -15 deg. crossflow angle. This exception is the only caveat preventing the proposal of acceptable alternative configurations for the LH2 trays as well. Structural assessment of all tray loads and tray response measurements from launches following the Shuttle Return To Flight with the existing PAL Ramps will determine the acceptability of these PAL Ramp alternatives

Morphine self-administration, food-reinforced, and avoidance behaviors in rhesus monkeys

1. A fixed interval-fixed ratio chain of behavior was maintained for periods as long as 6 months by intravenously administered morphine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46396/1/213_2004_Article_BF00413045.pd

The Heavy Photon Search test detector

The Heavy Photon Search (HPS), an experiment to search for a hidden sector photon in fixed target electroproduction, is preparing for installation at the Thomas Jefferson National Accelerator Facility (JLab) in the Fall of 2014. As the first stage of this project, the HPS Test Run apparatus was constructed and operated in 2012 to demonstrate the experiment׳s technical feasibility and to confirm that the trigger rates and occupancies are as expected. This paper describes the HPS Test Run apparatus and readout electronics and its performance. In this setting, a heavy photon can be identified as a narrow peak in the e+e− invariant mass spectrum above the trident background or as a narrow invariant mass peak with a decay vertex displaced from the production target, so charged particle tracking and vertexing are needed for its detection. In the HPS Test Run, charged particles are measured with a compact forward silicon microstrip tracker inside a dipole magnet. Electromagnetic showers are detected in a PbW04 crystal calorimeter situated behind the magnet, and are used to trigger the experiment and identify electrons and positrons. Both detectors are placed close to the beam line and split top-bottom. This arrangement provides sensitivity to low-mass heavy photons, allows clear passage of the unscattered beam, and avoids the spray of degraded electrons coming from the target. The discrimination between prompt and displaced e+e− pairs requires the first layer of silicon sensors be placed only 10 cm downstream of the target. The expected signal is small, and the trident background huge, so the experiment requires very large statistics. Accordingly, the HPS Test Run utilizes high-rate readout and data acquisition electronics and a fast trigger to exploit the essentially 100% duty cycle of the CEBAF accelerator at JLab