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PubMed1997

Severe long-term 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonism in the vervet monkey (Cercopithecus aethiops sabaeus).

The neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) produces parkinsonian neurochemical and functional deficits in human and non-human primates. The utility of MPTP-induced parkinsonism in monkeys as an animal model of Parkinson's disease would be greater if it produced a persistent and stable behavioural syndrome so that the effects of novel therapeutic treatments can be accurately assessed. Further, the claim that many species including primates spontaneously recover from MPTP is a significant difference from idiopathic Parkinson's disease. This experiment focused on the long-term (six months) persistence of behavioural deficits in severely and moderately parkinsonian monkeys. The severity of the syndrome was based on a quantitative and objective measure of parkinsonism. Adult male African green (vervet) monkeys (Cercopithecus aethiops sabaeus) were treated with MPTP (cumulative dose 2.5 mg/kg over five days), and six were saline-control treated. MPTP-treated subjects were examined in two groups: those that were severely parkinsonian ("severe" group, n = 11) and those that were moderately impaired ("moderate" group, n = 5) the month after treatment. Summary factor scores were examined reflecting abnormal ("parkinsonian") behaviour and normal "healthy" behaviour. Subjects that displayed severe parkinsonism the month after MPTP were found to show stable and severe parkinsonism for the time period studied. In contrast, the group of animals that initially were moderately parkinsonian did not show a stable deficit during the study. These data suggest that the initial severity of the deficit is an important predictor of outcome. None the less, stable parkinsonism can be observed in severely parkinsonian subjects despite variability in the severity of the impairment in response to MPTP treatment. Two moderately and three severely affected subjects were studied for more than six months and they appeared to show equivalent scores at six months compared with between 11 to 19 months after MPTP administration. MPTP-treatment in the vervet monkey can result in persistent long-term deficits and therefore provides an excellent phenomenological as well as neuropathological model of Parkinson's disease.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed1990

Cognitive and motor deficits in the performance of an object retrieval task with a barrier-detour in monkeys (Cercopithecus aethiops sabaeus) treated with MPTP: long-term performance and effect of transparency of the barrier.

To assess the stability of neural deficits produced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), the performance of monkeys on an object retrieval (detour) task was studied. The task required retrieval of a banana slice from a transparent box open on one side and fastened to a tray in front of the cage. The orientation of the open side, position on the tray, and position of the banana in the box were manipulated to vary the difficulty of the trials. Six African green monkeys (Cercopithecus aethiops sabaeus) were treated with MPTP (1.5-1.6 mg/kg cumulative doses over 4-5 days) and compared with 5 saline-treated control monkeys. The MPTP-treated monkeys had no gross neurological deficits but did have motor and cognitive deficits during acquisition of the object retrieval task 8-12 months after treatment (J. R. Taylor, Elsworth, Roth, Sladek, & Redmond, in press). Performance on the task was examined for 3 months after it had been learned. The MPTP-treated subjects reached at the barrier (transparent side) significantly more than controls and were less successful at retrieving the reward on the 1st reach than controls. Although they took longer to initiate the reach and had more motor problems than controls, they were as likely as controls to retrieve the reward in the end. These deficits remained stable throughout testing. An opaque but otherwise identical box was used randomly on some trials. MPTP-treated subjects decreased barrier reaches to control levels on trials in which the opaque box was used, whereas motor problems increased compared with trials in which the transparent box was used. The task can detect subtle performance deficits similar to those found in Parkinson's disease.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed1992

Silhouettes elicit alarm calls from captive vervet monkeys (Cercopithecus aethiops).

In Part 1, we analyzed alarm calls produced by captive vervets (Cercopithecus aethiops) in response to naturally occurring stimuli. Females and juveniles regularly alarm called to airplanes, birds, and barking dogs. Juvenile females accounted for 60% of these alarm calls. In Part 2, we isolated several monkeys from the colony and presented them with life-sized silhouettes of a leopard, snake, eagle, baboon, vervet, and goose. Adult monkeys alarm called more than did juveniles. Alarm calls were elicited by leopard, snake, baboon, and vervet silhouettes, but none were elicited by eagle or goose silhouettes. Some leopard and snake alarm calls matched those recorded in the wild in the context of the vervets' natural predators. Results indicate that silhouette stimuli are a useful technique for eliciting monkey vocalizations in the laboratory.

Animals↗

PubMed1993

Ontogeny of foraging behavior in wild vervet monkeys (Cercopithecus aethiops): social interactions and survival.

The ontogeny of feeding behavior was explored by making observations of 32 vervet monkey (Cercopithecus aethiops) infants in Amboseli National Park, Kenya. In contrast to adults and juveniles, infants appear to treat all primary food products in their diet as equally valuable. These age-related differences may reflect differences in food preference. To assess social influences, feeding synchrony between mother and infant was explored. From birth to 2 months, infants typically fed asynchronously with respect to their mother's feeding bouts. From 2 to 12 months, however, most infants fed at the same time and on the same food items as their mothers. Among infants, there was a significant positive association between the proportion of synchronous, same food bouts and the probability of survival. Variation among infants in access to resources and encounter rates with predators did not, however, have a significant effect on survival.

Aging↗

PubMed1994

Perception of chirps by Sykes's monkeys (Cercopithecus albogularis) and humans (Homo sapiens).

Four Sykes's monkeys (Cercopithecus albogularis) and 4 humans (Homo sapiens) discriminated among 12 chirps presented in a repeating background paradigm. The test stimuli consisted of sets of 4 chirps recorded from Sykes's monkeys, red-tailed monkeys (C. ascanius), and small East African birds. Reaction times were submitted to a multidimensional scaling analysis. All monkey listeners perceived the bird chirps as similar to each other and distinct from the monkey calls, whereas 3 of the 4 human listeners had difficulty distinguishing the bird chirps from the monkey calls. Both human and monkey subjects tended to perceive Sykes's and red-tailed monkey calls as very similar to one another, but the degree of perceived similarity was greatest for the monkey listeners. The data suggest that the perceptual map of these calls is influenced by their biological significance in nature.

Animals↗

PubMed2000

Hand preferences in unimanual and bimanual feeding by wild vervet monkeys (Cercopithecus aethiops).

Lateral preference was examined in spontaneous feeding actions in 2 troops of wild vervet monkeys (Cercopithecus aethiops). Processing of 4 foods (termites, leaf shoots, sugarcane, and fruit) was studied. Actions included unimanual reaching to moving objects, operating from an unstable posture, and coordinated bimanual processing. Between 19 and 31 subjects were available, according to the task. In 2 tasks, laterality of 2 independent stages was measured separately, giving 6 measures in all. On 4 of these measures, most monkeys were ambipreferent, and only a few showed significant hand preferences. Only for termite feeding and detaching material from fruits did the majority show significant lateralization; no tasks elicited exclusive use of 1 hand. Preference appeared labile, because in 2 tasks, population trends reversed with increasing age. No population trends to left or right were found; instead, these monkeys showed ambilaterality, with lateralization associated with task complexity.

Animals↗

PubMed2001

Individual differences in response to a stranger: social impulsivity as a dimension of temperament in vervet monkeys (Cercopithecus aethiops sabaeus).

Social impulsivity in response to a stranger was assessed in male vervet monkeys (Cercopithecus aethiops sabaeus) using the Intruder Challenge Test. Vervets (N = 128, ages 3-18 years) were presented with an unfamiliar adult male at the periphery of the home enclosure. An index of impulsivity reflecting variation in the tendency to rapidly approach, engage, and challenge the intruder was derived from factor analysis of behavioral responses. Scale reliability (alpha = .84) and test-retest consistency (intraclass correlation = .83) were high, indicating that this index reliably and efficiently measures a stable aspect of temperament from impulsive to inhibited. Impulsivity scores peaked at age 4, when vervet males typically emigrate from the natal group. The highest ranking males in each group were more likely to score in the moderate range, whereas lower ranking males were more likely to score in the highest (impulsive) or lowest (inhibited) quartiles.

Aggression↗

PubMed1999

The maturation of sperm motility in the epididymis and vas deferens of the vervet monkey, Cercopithecus aethiops.

Among the diverse facets of sperm maturation, changes in motility are conspicuous and hence studies of sperm kinematics might provide good indices for sperm maturation. Accordingly, the maturation of sperm motility in the epididymis and vas deferens of the vervet monkey, Cercopithecus aethiops, was assessed using a computer-aided sperm motility analysis system. The results revealed clear trends in the development of both sperm motility per se and in the movement characteristics of motile spermatozoa from different regions of the epididymis, the vas deferens and the ejaculate, reflecting maturational changes associated with the attainment of functional motility and fertility. Motion of spermatozoa from the caput epididymis was sluggish and irregular. As the spermatozoa moved through the corpus epididymis, motility increased sharply, and continued to improve through the cauda epididymis and vas deferens. Despite the high proportion of motile cells, full maturation of motion capabilities was not completed in spermatozoa from the corpus epididymis. Only once spermatozoa had reached the cauda epididymis and vas deferens did they attain their full vigour, and swam rapidly (greater VCL, VSL and VAP) with straightline trajectories (greater LIN, WOB and STR; lower ALH, MAD and CURV). After acquiring their maximal percentage motility and progressive velocity in the cauda epididymis and vas deferens, a slight decline in motility and vigour occurred in ejaculated spermatozoa, and was possibly associated with the ageing of stored spermatozoa. The results from this investigation have revealed clear trends in the maturation of the motility of vervet monkey spermatozoa during their transit through the epididymis and vas deferens and final emergence in the ejaculate, and have provided crucial baseline information on the reproductive physiology of this potentially valuable biomedical model to serve as a reference for future studies in reproductive toxicology.

Animals↗

PubMed1998

Nitric oxide production in vervet monkeys (Cercopithecus aethiops) infected with Trypanosoma brucei.

A retrospective study of nitrate concentration in serum and cerebrospinal fluid (CSF) from vervet monkeys (Cercopithecus aethiops) infected with Trypanosoma brucei was undertaken. Serum nitrate was significantly elevated in parasitaemic animals. CSF nitrate detection correlated with the presence of parasites in the CNS. The results provide evidence for the production of nitric oxide (NO) in response to infection in a primate model of human African trypanosomiasis and provide the basis for the use of such a model in studies of the immunopathological effects of NO in human trypanosomiasis.

Animals↗

PubMed2003

Cytochrome P450-dependent metabolism of l-deprenyl in monkey (Cercopithecus aethiops) and C57BL/6 mouse brain microsomal preparations.

The aim of the present investigation was to characterize the cytochrome P450 (CYP)-dependent metabolism of l-deprenyl by brain microsomal preparations obtained from two different animal models that have been extensively used in Parkinson's disease studies, namely monkey (Cercopithecus aethiops) and C57BL/6 mouse. In monkey brain microsomal fractions, the apparent Km values for methamphetamine formation from l-deprenyl were 67.8 +/- 1.0 and 72.0 +/- 1.6 microm, in the cortex and striatum, respectively. Similarly, for nordeprenyl formation from l-deprenyl, Km values in cortex and striatum were 21.3 +/- 3.2 and 27.3 +/- 4.0 microm, respectively. Both metabolic pathways appear to be more efficient in the cortex than in the striatum as the Vmax for microsomal preparation was lower in the striatum for the formation of both metabolites. The formation rate of l-methamphetamine was up to one order of magnitude greater than that of nordeprenyl. Inhibition analysis of both pathways in monkey brain suggested that l-methamphetamine formation is catalysed by CYP2A and CYP3A, whereas only CYP3A appears to be involved in nordeprenyl formation. With microsomal preparations from whole brain of C57BL/6 mice, the only l-deprenyl metabolite that could be detected was methamphetamine and the Km and Vmax values were similar to those determined in monkey cortex (53.6 +/- 2.9 microm and 33.9 +/- 0.4 pmol/min/mg protein, respectively). 4-Methylpyrazole selectively inhibited methamphetamine formation, suggesting the involvement of CYP2E1. In conclusion, the present study indicates that l-deprenyl is effectively metabolised by CYP-dependent oxidases in the brain, giving rise mainly to the formation of methamphetamine, which has been suggested to play a role in the pharmacological effects of the parent drug. The results also demonstrate that there are differences between species in CYP-dependent metabolism of l-deprenyl.

Animals↗

PubMed1987

A comparison of the effects of soya-bean protein and casein on bile composition, cholelithiasis and serum lipoprotein lipids in the vervet monkey (Cercopithecus aethiops).

1. Two groups of vervet monkeys (Cercopithecus aethiops) were fed on high-cholesterol diets which differed only with respect to the protein source. In one group casein was the only protein source, while the other group received only soya-bean protein. 2. Samples of blood, bile and liver biopsy material were collected at the commencement of the study and at 3-monthly intervals until termination 12 months later. 3. At the end of the experimental period all the animals (n 19) had high plasma cholesterol levels and had developed pigment gallstones, the compositions and weights of which were not related to the protein source or to plasma cholesterol levels. Gallstone weight was related to the presence of acidic and sulphated mucins in gallbladder mucosa. We were also unable to confirm the hypocholesterolaemic effect of soya-bean protein which has been demonstrated previously in rhesus monkeys and hamsters. Bile composition and plasma lipids did not differ significantly between the casein-fed and soya-bean fed animals. Lithogenic index was below 1 for both groups and did not differ significantly between the two groups. 4. No significant difference was found in the severity of cholelithiasis between the casein-fed and the soya-bean-fed animals.

Animals↗

PubMed1984

Variability in blood pressure response to dietary sodium intake among African green monkeys (Cercopithecus aethiops).

Since salt-sensitivity to blood pressure (BP) response is a species-related phenomenon, the response of BP to dietary sodium was examined in 14 adult male African green monkeys (Cercopithecus aethiops). The animals were exposed to graded increase of dietary NaCl at 0 (control), 3.0, 4.5, and 6.0%, respectively for 45, 139, 37, and 90 days. Systolic and diastolic BP and body weights were measured twice weekly. Body weight did not differ significantly between successive diets. The mean (+/- SD) systolic/diastolic BP for control, 3.0, 4.5, and 6.0% NaCl diets were 88.8 +/- 15.4/65.9 +/- 13.7, 101.9 +/- 17.6/72.1 +/- 13.0, 90.5 +/- 20.9/62.2 +/- 16.2, and 115.3 +/- 22.6/81.0 +/- 16.4, respectively. BP changes between successive diets were significant (p less than 0.05). Monkeys with high or low initial mean arterial BP levels on control diet tended to maintain the same order with significantly high correlations between BP levels for successive diet periods (r = 0.88 to 0.95, p less than 0.0001). Thus as a group, this nonhuman primate species responds to increased NaCl intake with elevated mean systolic and diastolic BP. Individual variations in salt sensitivity and consistency in persistence of BP levels in this species has bearing on human hypertension.

Animals↗

PubMed1990

Characterization of a primate model of hypertension. The response of hypertensive and normotensive male vervets (Cercopithecus aethiops) to cold pressor stress, captopril administration, and acute bolus of atrial natriuretic factor.

In feral populations of African green monkeys or vervets (Cercopithecus aethiops), between 5 and 15% of adults have spontaneously elevated blood pressure (BP). We report here the initial biological and pharmacological characterization of this potential animal model of hypertension. Captive male monkeys with elevated systolic pressures show a modest pressure increase in response to stressors such as capture, phlebotomy and cold challenge. Acute captopril administration lowers BP in monkeys with high blood pressure (HBP), but has no effect on BP in control animals. Furosemide does not acutely reduce BP. Animals with elevated BPs have lower levels of angiotensin II than do age- and weight-matched controls. An acute infusion of atrial natriuretic factor (ANF) diminishes BP and stimulates urinary output in control and HBP vervets. However, both effects are more pronounced in animals with HBP. Heart rate is not affected by any of the experimental manipulations. Taken together, these data suggest that African green monkeys with spontaneously elevated BP may be a useful experimental model for particular types of human hypertension. Additional studies are required to complete the endocrine and pharmacological characterization of individual animals with HBP.

Analysis of Variance↗

PubMed1976

Immunity in plague: protection induced in Cercopithecus aethiops by oral administration of live, attenuated Yersinia pestis.

A live, attenuated Yersinia pestis vaccine, designated EV76 (Paris) F, was pathogenic in Cercopithecus aethiops when administered parenterally. Although an oral dose of 10(9) colone-forming units of the vaccine was nonfatal to vervets, a transient but severe gastrointestinal disturbance resulted in four of 12 animals. Seven immunized vervets were protected against intradermal challenge. The remaining five vervets without serologic reactions and five untreated controls died from typical bubonic (septicemic) plague within seven days. General reactions after vaccination were not predictive of later-developing immunity, which appeared to correlate with the production of Fraction I-specific antibodies. Marked differences in immunity were noted with two methods of vaccine administration (incorporation into bananas and dropping into the mouth). This finding supported the prior observation that the oral mucosa is the major portal of entry for this strain of vaccine. Local reactions in the buccal cavity after feeding were negligible. Thus this strain of Y. pestis is a nonlethal, effective weapon against bubonic plague in a susceptible species.

Administration, Oral↗

PubMed1998

Induction of cell proliferation and differentiation in the pancreas of the adult Vervet monkey (Cercopithecus aethiops): preliminary results.

Cellophane wrapping of the adult Syrian golden hamster pancreas has been found to result in ductular cell proliferation leading to islet regeneration. Injection of cytosol from a cellophane-wrapped pancreas into normal or diabetic hamsters evoked a similar response. In view of the therapeutic potential of the active substance in this cytosol, it was decided to investigate whether a similar response could be achieved in a primate. In normal adult Vervet monkey (Cercopithecus aethiops) pancreas, proliferation is seen only rarely in islet cells and occasionally in duct and acinar cells. Immunohistochemical investigation of normal Vervet monkey pancreas (n = 4) and 14 days (n = 2) and 56 days (n = 1) after cellophane wrapping of the Vervet monkey pancreas revealed a slight increase in proliferation of islet and acinar cells and a larger increase in proliferation of duct cells and in total endocrine cell volume. The results suggest that there is a latent developmental capability in the adult primate pancreas.

Animals↗

PubMed1996

Simian immunodeficiency virus infection in a patas monkey (Erythrocebus patas): evidence for cross-species transmission from African green monkeys (Cercopithecus aethiops sabaeus) in the wild.

Socio-ethological studies on troops of African green monkeys (AGMs) (Cercopithecus aethiops sabaeus) and patas monkeys (Erythrocebus patas) in Senegal have documented physical contacts between these two species. Elevated simian immunodeficiency virus (SIV) seroprevalence rates have been reported for the different AGM subspecies. We report here the extent to which patas monkeys are infected and compare the relatedness of the viruses isolated from theses two different species. Among the 85 AGMs and 54 patas monkeys studied, 47% of 7.5%, respectively, had antibodies that cross-reacted with HIV-2 envelope proteins. From two AGMs a virus was isolated. From the patas monkeys, virus isolation was generally not possible, but from one animal that was ill a virus designated pamG31 was amplified by PCR. In addition, for the two SIVagm isolates, an 830 bp region spanning the env and nef genes was amplified and sequenced. Comparisons of sequences from the env/nef region revealed 80% identity between pam G31 and SIVagm isolates from AGMs of the sabaeus subspecies, and 94% identity between the two SIVagm isolates. Phylogenetic analysis showed that pamG31 belongs to the SIVagm sabaeus subgroup. This is the first report of a lentiviral infection in a patas monkey. The close genetic relatedness between pamG31 and SIVagm sabaeus viruses is a strong argument in favour of cross-species transmission of SIV between AGMs and patas monkeys in the wild. For these reasons, we propose to refer to this patas virus as SIVagm-pamG31.

Amino Acid Sequence↗

PubMed1998

Polymorphism of Mhc-DRB alleles in Cercopithecus aethiops (green monkey): generation and functionality.

DRB genes have been studied for the first time in green monkeys (Cercopithecus aethiops). Eleven new DRB alleles (exon 2, exon 3) have been obtained and sequenced from cDNA. A limited number of lineages have been identified: DRB1*03 (4 alleles), DRB1*07 (3 alleles), DRB5 (1 allele), DRB*w6 (1 allele), and DRB*w7 (2 alleles). The existence of Ceae-DRB1 duplications is supported by the finding of 3 DRB1 alleles in 3 different individuals. Ceae-DRB1*0701 may be non-functional because it bears serine at position 82, which hinders molecule surface expression in mice; the allele is only found in Ceae-DRB duplicated haplotypes. Base changes in cDNA Ceae-DRB alleles are consistent with the generation of polymorphism by point mutations or short segment exchanges between alleles. The eleven green monkey DRB alleles meet the requirements for functionality as antigen-presenting molecules (perhaps, excluding DRB1*0701), since: 1) they have been isolated from cDNA and do not present deletions, insertions or stop codons: 2) structural motifs necessary for a correct folding of the molecule, for the formation of DR/DR dimers and for CD4 interactions are conserved, and 3) the number of non-synonymous substitutions is higher than the number of synonymous substitutions in the peptide binding region (PBR), while the contrary holds true for the non-PBR region.

Alleles↗

PubMed1996

SIVagm incidence over two decades in a natural population of Ethiopian grivet monkeys (Cercopithecus aethiops aethiops).

The incidence of SIVagm seropositivity in a natural population of Ethiopian grivet monkeys (Cercopithecus aethiops aethiops) is investigated using plasma samples collected in 1973, and shown to be similar to that reported from the same population in 1990-91. Results tend to support our previous conclusions: endemic SIVagm has little or no impact on the survival of wild grivet monkeys, and the virus is transmitted almost always by sexual contact, occasionally by trauma, and rarely if ever maternally. Small differences between 1973 and 1990-93 suggest that the stress of drought years may raise the incidence of traumatic transmission, and temporarily depress transmission by sexual activity, in this population.

Animals↗