Selective autonomic blockade of conditioned and unconditioned cardiovascular changes in rhesus monkeys (Macaca mulatta).

Examined changes in heart rate and systolic and diastolic blood pressures in 8 rhesus monkeys during 6 sessions of differential classical conditioning. The conditioned stimuli consisted of tones differing in frequency, and the unconditioned stimuli consisted of tail shock. Both the CRs and UCRs consisted of increases in heart rate and in systolic and diastolic pressures, but blood pressure CRs sometimes occurred in the absence of heart rate CRs. In Exp II, graded doses of the selective blocking agents propranolol, phentolamine, and atropine methylnitrate were systemically administered to 4 of the Ss prior to additional conditioning sessions. Results suggest that the CRs and UCRs were mediated by both sympathetic and parasympathetic influences. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Thermal thresholds of the rhesus monkey (Macaca mulatta).

Measured thresholds to warming and cooling stimuli presented on the shaved skin of the inner thigh of 2 young male rhesus monkeys by the conditioned suppression method after the skin had been preadapted to 28, 30, 32, 34, 36, 38, and 40. C temperatures. Thresholds to warming stimuli decreased from .14 to .02. C, while thresholds to cooling stimuli increased from .05 to .28. C as the adapting temperature was increased from 28 to 40. C. In comparison to human thresholds, the Ss were more sensitive to changes in stimulator temperature at all adapting temperatures except to cooling at a 40. C adapting temperature. Data suggest that the Ss were able to discriminate between warming and cooling stimuli and that they responded to a change in sensation at the extreme adapting temperatures rather than to the quality of the sensation-warm or cool. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Extinction deficits in socially isolated rhesus monkeys (Macaca mulatta).

In a study with 18 5-yr-old rhesus monkeys, 6 Ss reared in total isolation made more unrewarded responses and took longer to stop responding in the face of nonreward than 12 Ss raised in partial isolation or normally. It is suggested that isolates have difficulty inhibiting high-probability responses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Matching within and between sense modalities in the monkey (Macaca mulatta).

Trained 18 rhesus monkeys on a series of visual matching problems and tested for cross-dimensional transfer. Performance of a true matching group was at the same time compared with that of a "false matching" (i.e., conditional reaction) group. Training was then given on a series of cross-modal (visual-tactual) matching (CMM) problems, again with true vs false matching comparisons. Finally, a test for CMM using a single-sample technique was given. Evidence was found for cross-dimensional transfer of visual matching, but none for differences between initial true and false visual, or cross-modal, matching tasks. Nor was evidence for a genuine CMM ability found in the results of the single-sample CMM tests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of phenobarbital and diazepam on imipramine-induced changes in blood pressure, heart rate and rectal temperature of rats

To investigate the safety of anticonvulsants in doses found equipotent in suppressing imipramine induced convulsions, the effects of diazepam (1.8 mg/kg) or phenobarbital (40 mg/kg) following a toxic dose of imipramine (50 mg/kg) on heart rate, blood pressure and body temperature were examined in male Wistar rats. Administration of imipramine alone resulted in significant decreases in blood pressure, heart rate and rectal temperature. Phenobarbital or diazepam alone failed to significantly affect any of these parameters apart from a slight reduction in rectal temperature seen with phenobarbital. Diazepam given after imipramine antagonized the imipramine-induced decrease in heart rate but increased the hypotensive and hypothermic effects. Phenobarbital failed to significantly affect the imipramine-induced changes in any of the physiological parameters studied. The present data suggests that phenobarbital may be preferable to diazepam in treatment of imipramine-induced convulsions.     

Emmetropization in the rhesus monkey (Macaca mulatta): birth to young adulthood

PURPOSE: To provide baseline measurements on the postnatal changes in refractive error, corneal curvature, and axial elongation of the eyes of normal monkeys. Little is known about the course of normal eye growth from birth to adolescence, particularly how refractive parameters co-vary during development. In animal models of ametropia, usually one eye is manipulated and the fellow eye serves as a control. However, given individual differences, and without baseline data, it is impossible to determine whether either eye develops normally. METHODS: Measurements were obtained on 237 rhesus monkeys, whose ages ranged from birth to 5 years. Examinations included cycloplegic refraction by retinoscopy, keratometry measurements, and A-scan ultrasound measurements of axial length. The time course of development was evaluated using a growth curve analysis appropriate for a mixture of cross-sectional and longitudinal data. RESULTS: At birth, all three parameters were normally distributed and only weakly correlated. Monkeys had +7 D (SD=2.3 D) of hyperopia, corneal power of 58 D (SD=1 D), and axial length of 13.2 mm (SD=0.4 mm). Refractive error ranged from +0.5 D to +14.5 D, with a mean difference between the two eyes of 0.5 D. Corneal curvature ranged from 61 D to 54 D, with a mean difference between the two eyes of 0.8 D. Axial length ranged from 12.0 mm to 14.2 mm, with a mean difference between the two eyes of 0.1 mm. Although the degree of hyperopia achieved asymptote, of + 2 D, shortly after 1 year of age, corneal curvature and axial length did not achieve asymptote until nearly 5 years of age. By this time, refractive error had declined by 5 D, corneal curvature had declined by 7 D, and axial length had increased by 6 mm. CONCLUSIONS: The magnitude of the individual differences that can occur in a small sample of experimental subjects is large enough to necessitate reference to age norms derived from a large population. Our results provide a baseline for studies of normal and abnormal eye growth and ametropia in primates. Our results also led to the confirmation of a set of "rules" that have been offered as an explanation of how these three parameters interact during emmetropization.     

The nocturnal behavior of caged rhesus monkeys (Macaca mulatta)

The behavior of rhesus monkeys (Macaca mulatta) was observed via videotape recording during the 12 hour period from 6.00 p.m. to 6.00 a.m. Adult animals were housed in male/female pairs under one of three cage conditions: individual cage, mating cage and a larger 'group' cage. 20 categories of behavior were assessed and the resultant behavior was described and quantitatively compared across cage conditions. The animals spent almost the entire night in a sitting position, either alone or while huddling with another animal. Sitting and huddling behavior are near-perfect complements to each other in terms of the frequency of occurrence; taken together they account for almost the entire nocturnal behavior. Other activity rarely displaces these behaviors. The animals tended to be relatively active in the early evening. As night fell, they settled down to relative inactivity, which they maintained until the morning. The activity level gradually increased as dawn approached.     

Differential effect of early enrichment and deprivation on learning in the rhesus monkey (Macaca mulatta).

Conducted an experiment with 24 rhesus monkeys to extend research findings concerning the effects of early experience on nonhuman primate learning ability. Enriched Ss tested in their home living environment performed more proficiently than Ss separated from their living environments and tested in an adjoining room. Further, Ss reared in enriched environments were superior to partially isolated controls on the complex oddity tasks but not on 2-choice discrimination or delayed-response problems. (33 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The development of auditory event related potentials in the rhesus monkey (Macaca mulatta)

Auditory event related potentials were recorded from neonatal, 3-month, and 3-year old rhesus monkeys. Auditory brainstem evoked responses (ABRs) were reliably recorded at all ages. ABR latencies decreased with age. Age effects were greater the more centrally generated the wave. Wave I amplitude decreased with age, Wave II increased, and Wave IV remained about the same. Stimulus rate effects were greater in neonates than older monkeys. Stimulus frequency also affected the ABR, but not differentially as a function of age. Recording montage had a significant effect on the recorded waveform. Wave I tended to be larger in amplitude in horizontal recordings and front-back recordings, while the later waves were relatively more prominent in more vertical montages. Middle latency evoked responses and late potentials were less reliably recorded than the ABR. Their reproducibility improved with age. Auditory event related potentials are promising measures of auditory function for research requiring nonhuman primate models of the developing human.     

Monoamine metabolite levels in CSF of SIV-infected rhesus monkeys (Macaca mulatta)

Increasing evidence suggests the involvement of the basal ganglia in HIV-1-infected patients. We used SIV-macaques, an animal model of HIV-1 infection, to investigate changes in CSF biogenic amine metabolites over time and compared them with control animals. The dopamine and serotonin metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA), were analysed by reverse-phase chromatography with electrochemical detection. DOPAC concentrations were significantly increased in SIV-infected animals compared with controls. 5-HIAA and HVA remained unchanged. However, the longitudinal assessment of metabolites up to 3 months post-infection revealed a significant increase in 5-HIAA. Our results reflect the effects of SIV early stage infection on monoamine systems in brain and further validate the simian model for AIDS research.     

The ultrastructural features of progestagen-induced decidual cells in the rhesus monkey (Macaca mulatta)

Five rhesus monkeys were treated with levonorgestrel-releasing intravaginal rings for 52 weeks. The rings were designed to provide a sustained release of ten times the human dose level of the hormone. Histological examination of the uterine endometrium showed widespread decidualisation of endometrial stromal cells. Ultrastructurally, two distinct cell types were identified: decidual and granular. Some of the decidual cells were ultrastructurally comparable with those reported elsewhere; however, in aproportion of these cells, intracisternal sequestration of the rough endoplasmic reticulum was widespread. The granular cells resembled those described in the metrial gland of rats and, as their name suggests, contained variable numbers of electron-dense granules.     

Monoamine distribution in primate brain. III. Catecholamine-containing varicosities in the hypothalamus of Macaca mulatta

The histochemical fluorescence technique of Falck and Hillarp was used to examine the distribution of catecholamine-containing varicostities within the hypothalamus of the rhesus monkey (Macaca mulatta). Varicosities were seen in heaviest concentrations within the periventricular area and the following nuclei: lateral and madial preoptic, supraoptic, paraventricular, arcuate and dorsomedial. Patterns observed presented striking similarities and dissimilarities to catecholamine distribution reported in the rat and car. Catecholaminergic perikarya were not observed routinely.     

Aerosolized staphylococcal enterotoxin B-induced pulmonary lesions in rhesus monkeys (Macaca mulatta)

The pathology of aerosolized staphylococcal enterotoxin B (SEB) was studied in the nonhuman primate. Six juvenile rhesus monkeys that received multiple lethal inhaled doses of SEB developed diarrhea and vomiting within 24 hr followed by depression, dyspnea, and shock. Three of 6 animals died by 52 hr. The most striking gross lesion in all 6 monkeys was diffuse severe pulmonary edema. Histologically, edema fluid was present within the peribronchiolar, peribronchial, and perivascular interstitium, alveolar septa, and alveoli. The adventitia of pulmonary vessels was infiltrated by lymphocytes, macrophages, and fewer neutrophils. Numerous large lymphocytes with occasional mitotic figures were within pulmonary vessels, often occluding alveolar capillaries. These cells were strongly immunoreactive with monoclonal antibodies against CD3, establishing them as T cells. Ultrastructurally, endothelial cell junctions were intact, and endothelial cells and type I pneumocytes contained numerous pinocytotic vesicles. Alveolar septal interstitial spaces were expanded by edema. The mechanism of these SEB-induced pulmonary lesions was not determined. We hypothesize that cytokine production by activated T cells may have caused vascular permeability changes leading to widespread pulmonary edema and shock.     

Characterization of centchroman binding protein in plasma of rhesus monkey (Macaca mulatta)

A boy with multicore myopathy associated with multiple pterygium syndrome and hypertrophic cardiomyopathy is described. Light microscopy of biopsy samples from the skeletal muscle and myocardium revealed multiple cores in the muscle fibers in the former but their absence in the latter. These results suggest that the pathogenesis of the histologic changes might differ between skeletal muscle and myocardium, and that further electron microscopic examination be done on both types of specimen. The prognosis of multicore myopathy is not usually good when cardiac involvement is present.     

Neuropathogenesis induced by rhesus cytomegalovirus in fetal rhesus monkeys (Macaca mulatta)

In a double-blind study, 655 sputum specimens were obtained from individuals suspected of having tuberculosis and were analyzed for the presence of Mycobacterium tuberculosis and rifampin susceptibility with use of a polymerase chain reaction (PCR)-based universal heteroduplex generator assay (PCR/UHG-Rif). Of the specimens containing viable M. tuberculosis, 100% of the smear-positive (n = 41) and 50% of the smear-negative (n = 6) specimens tested positive for the organism by PCR/UHG-Rif. Nineteen of 537 culture-negative specimens tested positive for M. tuberculosis by PCR/UHG-Rif and were from patients with confirmed tuberculosis who were receiving antituberculosis therapy at the time of specimen collection. Thirty-five specimens contained nontuberculous mycobacteria and were negative by PCR/UHG-Rif. Genotypic evidence of rifampin resistance in five of six culture-confirmed, rifampin-resistant isolates was obtained by PCR/UHG-Rif, yielding a sensitivity and specificity for the assay of 83% and 98.2%, respectively. These results demonstrate the feasibility of using a PCR-based assay directly on sputum specimens for simultaneous detection of M. tuberculosis and rifampin susceptibility, and they suggest that patients with smear-positive, untreated tuberculosis and those presenting with suspected drug-resistant tuberculosis are the most appropriate groups for testing by PCR/UHG-Rif.     

A biphasic developmental pattern of circulating leptin in the male rhesus macaque (Macaca mulatta)

To help elucidate the physiological role of leptin during somatic and sexual maturation, circulating concentrations of leptin were measured in 36 male rhesus monkeys of ages ranging from 0-20 yr. The body weight of these animals showed a steady increase of approximately 1 kg/yr during the first decade of life and reached a plateau at approximately 13 yr. In contrast, serum leptin concentrations showed a biphasic developmental pattern, which was highlighted by a strong negative correlation with body weight (r = -0.74, P < 0.001) before the onset of puberty (at approximately 3.5 yr) and by a strong positive correlation afterward (r = 0.77, P < 0.001). Overall, the developmental changes in serum leptin concentrations closely mimicked the expected developmental changes in serum testosterone concentrations (r = 0.62, P < 0.001), which were highly elevated at birth, fell to basal levels during the juvenile phase of development, and gradually rose again after the initiation of puberty. However, mean serum leptin concentrations during the peripubertal period itself (3-5 yr) were significantly lower (P < 0.01) than those observed during the first year of life or those observed in fully mature adults (i.e. > 7 yr) (3.5 +/- 0.3, 1.4 +/- 0.2, and 3.3 +/- 0.6 ng/ml, respectively). These data demonstrate that the role of leptin in energy homeostasis of primates is more than a simple linear relationship, being highly dependent upon the developmental age. Furthermore, the data do not support the hypothesis that leptin plays a major role in triggering the onset of puberty in primates, although the strong correlation between serum concentrations of leptin and testosterone suggests that the secretion of these two hormones may be causally linked.     

Evaluation of consecutively placed unloaded root-form and plate-form implants in adult Macaca mulatta monkeys

The present paper describes 18 consecutively-treated non-human primates (Macaca mulatta) as part of a balanced block design study of 36 animals to examine osseointegration in root- and plate-form implants prepared by atraumatic preparation of bone. Clinical measurements around selected teeth and digital radiology were utilized to monitor periodontal disease and bone deposition around the unloaded implants. Once a month scaling procedures were utilized as a means of preventing further advance of periodontal disease. Results indicate that once-monthly regimen of scaling and root planing can prevent attachment loss of natural teeth and will not interfere with the healing of either type of implant; once-monthly scalings produce significant reduction in redness (P < .05) and reduced probing depths (P = .01). A second finding is that both root and blade implants show radiographic evidence of osseointegration in this primate model. The quantitative analysis demonstrates bone gain is not stabilized until 6 months after healing. The data may indicate that occlusal loading of mandibular implants at 3 months may be premature.     

Prefrontal control of conditioned suppression and associated cardiovascular variables in the monkey (Macaca mulatta).

Trained 17 male rhesus monkeys in a discriminated conditioned emotional responses paradigm. The discriminated conditioned response (CR) complex consisted of barpress suppression, increased terminal aortic blood flow, and increased arterial pressure. Barpress suppression and blood-flow responses were temporarily eliminated by single-stage bilateral prefrontal lobectomy but not by extensive posterior cortical ablation, 2-stage prefrontal lobe removal, or 3-stage prefrontal cortical surface ablation. The blood pressure CR was attenuated by almost every surgical operation. The changes in heart rate paralleled changes in general activity. Data indicate that the prefrontal lobes influenced the conditioned suppression of ongoing rewarded behavior and the vascular responses accompanying the suppression. The time course for recovery of the somatic CR after lobectomy differed from those of the cardiovascular CRs. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)