Buprenorphine suppresses cocaine self-administration by rhesus monkeys

Cocaine abuse has reached epidemic proportions in the United States, and the search for an effective pharmacotherapy continues. Because primates self-administer most of the drugs abused by humans, they can be used to predict the abuse liability of new drugs and for preclinical evaluation of new pharmacotherapies for drug abuse treatment. Daily administration of buprenorphine (an opioid mixed agonist-antagonist) significantly suppressed cocaine self-administration by rhesus monkeys for 30 consecutive days. The effects of buprenorphine were dose-dependent. The suppression of cocaine self-administration by buprenorphine did not reflect a generalized suppression of behavior. These data suggest that buprenorphine would be a useful pharmacotherapy for treatment of cocaine abuse. Because buprenorphine is a safe and effective pharmacotherapy for heroin dependence, buprenorphine treatment may also attenuate dual abuse of cocaine and heroin.     

Autoimmune chorioretinitis in rhesus monkeys

Monkeys injected with monkey retinal tissue incorporated in Freunld's complete adjuvant developed ocular lesions characterized by choroiditic patches in the fundus periphery and sheathing of retinal vessels. Bovine retina, monkey choroid plexus, and guinea pig kidney were ineffective in this respect.     

Natural occurrence of malaria in rhesus monkeys

A tone ending in unavoidable electric shock was periodically presented to pigeons while they pecked a key for food. When pecking was completely disrupted by tone, shock was disconnected, and the training tone and tones having new frequencies were presented. Initially the gradient of generalization was broad; as testing proceeded, however, the gradient narrowed severely.     

Sexual behavior in rhesus monkeys after vasectomy

Vasectomy had no statistically significant effect on the sexual behavior of vigorous adult rhesus monkeys. Of two groups of males matched for level of sexual performance, one was vasectomized and the other underwent sham vasectomy. In sex tests administered within the month after surgery, the groups showed no difference (P .05) in rate of mounting, intromission, or ejaculation, or in any other measure of sexual or sex-related behaviors.     

Induction of AIDS in rhesus monkeys by molecularly cloned simian immunodeficiency virus

Better understanding of the pathogenesis of acquired immunodeficiency syndrome (AIDS) would be greatly facilitated by a relevant animal model that uses molecularly cloned virus of defined sequence to induce the disease. Such a system would also be of great value for AIDS vaccine research. An infectious molecular clone of simian immunodeficiency virus (SIV) was identified that induces AIDS in common rhesus monkeys in a time frame suitable for laboratory investigation. These results provide another strong link in the chain of evidence for the viral etiology of AIDS. More importantly, they define a system for molecular dissection of the determinants of AIDS pathogenesis.     

Hyperphagia and polydipsia in socially isolated rhesus monkeys

Three rhesus monkeys which had been isolated from social contact during their first year of life persistently overate and overdrank during adulthood. These monkeys ingested approximately twice as much fluid and food as the control animals reared normally.     

Morphine: conditioned increases in self-administration in rhesus monkeys

Operant responding in three monkeys was maintained by intravenous presentations of morphine. Nalorphine produced reliable increases in morphine-reinforced responding. With successive daily nalorphine injections there was a decreased latency of self-administration responding for morphine, and substituted saline injections produced conditioned increases in morphine-reinforced responding.     

Calcification of the permanent first mandibular molar in rhesus monkeys

Evidence suggests that in rhesus monkeys calcification in the mandibular permanent first molar commences much earlier than has been previously reported. This tooth is the first secondary dental element to calcify, as it is in man.     

Aging in rhesus monkeys: relevance to human health interventions

Progress in gerontological research has been promoted through the use of numerous animal models, which have helped identify possible mechanisms of aging and age-related chronic diseases and evaluate possible interventions with potential relevance to human aging and disease. Further development of nonhuman primate models, particularly rhesus monkeys, could accelerate this progress, because their closer genetic relationship to humans produces a highly similar aging phenotype. Because the relatively long lives of primates increase the administrative and economic demands on research involving them, new emphasis has emerged on increasing the efficient use of these valuable resources through cooperative, interdisciplinary research.     

Rank of mothers and sons in bands of rhesus monkeys

In bands of free-ranging macaques, adolescent males typically leave their mothers in the central part of the band and assume low social rank at the periphery. But the adolescent sons of high-ranking mothers may remain central and rise to high rank without becoming peripheral.     

Control of viremia and prevention of clinical AIDS in rhesus monkeys by cytokine-augmented DNA vaccination

With accumulating evidence indicating the importance of cytotoxic T lymphocytes (CTLs) in containing human immunodeficiency virus-1 (HIV-1) replication in infected individuals, strategies are being pursued to elicit virus-specific CTLs with prototype HIV-1 vaccines. Here, we report the protective efficacy of vaccine-elicited immune responses against a pathogenic SHIV-89.6P challenge in rhesus monkeys. Immune responses were elicited by DNA vaccines expressing SIVmac239 Gag and HIV-1 89.6P Env, augmented by the administration of the purified fusion protein IL-2/Ig, consisting of interleukin-2 (IL-2) and the Fc portion of immunoglobulin G (IgG), or a plasmid encoding IL-2/Ig. After SHIV-89.6P infection, sham-vaccinated monkeys developed weak CTL responses, rapid loss of CD4+ T cells, no virus-specific CD4+ T cell responses, high setpoint viral loads, significant clinical disease progression, and death in half of the animals by day 140 after challenge. In contrast, all monkeys that received the DNA vaccines augmented with IL-2/Ig were infected, but demonstrated potent secondary CTL responses, stable CD4+ T cell counts, preserved virus-specific CD4+ T cell responses, low to undetectable setpoint viral loads, and no evidence of clinical disease or mortality by day 140 after challenge.     

Rapid production of acute disseminated encephalomyelitis in rhesus monkeys by injection of brain tissue with adjuvants

Rapid production in the monkey of a pathological condition resembling acute disseminated encephalomyelitis, marked by demyelination, can be achieved by the use of adjuvants added to rabbit brain emulsions.     

Free-ranging rhesus monkeys: age and sex differences in individual activity patterns

Two hundred thirty of the feral rhesus monkeys on Cayo Santiago were observed individually for postural adjustments, locomotor behavior, manipulation, and other nonsocial activities. Both form and frequency of activity were influenced strongly by age; sex differences were minimal. Most activities decreased with age, but head movements, presumably reflecting visual scanning, were more frequent in adults.     

Dexamethasone fails to suppress beta-endorphin plasma concentrations in humans and rhesus monkeys

In humans and rhesus monkeys, dexamethasone decreased concentrations of plasma cortisol but did not alter circulating beta-endorphin immunoreactivity. Contrary to current theory suggesting that pituitary beta-endorphin and adrenocorticotropic hormone are controlled by identical regulatory mechanisms for synthesis and release, our evidence suggests that in higher primates the established glucocorticoid feedback mechanism for the adrenocorticotropic hormone-cortisol system does not regulate beta-endorphin secretion in the same way.     

Redirection of filial attachments in rhesus monkeys: dogs as mother surrogates

Rhesus infants raised from birth with their mothers, age-mates, or cloth surrogates for periods varying fronm 1 to 10 months were separated from these objects and placed with dogs. Contrary to previous suggestions that were consistent with the notions of a critical period for attachment formation and irreversibility of filial bonds, the monkeys formed strong and specific attachments to their canine surrogates.     

Defensive behaviors in infant rhesus monkeys: environmental cues and neurochemical regulation

To survive, primates must detect danger in time to activate appropriate defensive behaviors. In this study, the defensive behaviors of infant rhesus monkeys exposed to humans were characterized. It was observed that the direction of the human's gaze is a potent cue for the infant. Infants separated from their mothers were active and emitted frequent distress vocalizations. When a human entered the room but did not look at the infant, it became silent and froze in one position. If the human stared at the infant, it responded with aggressive barking. Alterations of the opiate system affected the frequency of the infant's distress calls without affecting barking and freezing, whereas benzodiazepine administration selectively reduced barking and freezing. This suggests that opiate and benzodiazepine systems regulate specific defensive behaviors in primates and that these systems work together to mediate behavioral responses important for survival.     

Modification of cortically induced responses in brain stem by shift of attention in monkeys

The frequency of lethal mutations occurring in Drosophila melanogaster was reduced by approximately one-half when irradiated males were treated with actinomycin D, which also inhibited the appearance of melanotic atypical growths in the strain used for the study.     

Mobile DNA in Old World monkeys: a glimpse through the rhesus macaque genome

The completion of the draft sequence of the rhesus macaque genome allowed us to study the genomic composition and evolution of transposable elements in this representative of the Old World monkey lineage, a group of diverse primates closely related to humans. The L1 family of long interspersed elements appears to have evolved as a single lineage, and Alu elements have evolved into four currently active lineages. We also found evidence of elevated horizontal transmissions of retroviruses and the absence of DNA transposon activity in the Old World monkey lineage. In addition, approximately 100 precursors of composite SVA (short interspersed element, variable number of tandem repeat, and Alu) elements were identified, with the majority being shared by the common ancestor of humans and rhesus macaques. Mobile elements compose roughly 50% of primate genomes, and our findings illustrate their diversity and strong influence on genome evolution between closely related species.