Primates Rhesus Research Articles

Determining genetic background in captive stocks of cynomolgus macaques (Macaca fascicularis)

As in other model organisms, genetic background in the non-human primates Macaca mulatta and Macaca fascicularis is an experimental variable that affects the response of other study variables. Genetic background in model organisms is manipulated by breeding schemes but is generally pre-determined by the source population used to found captive stocks. In M. fascicularis three such sources have been distinguished, however, these are not routinely taken into consideration when designing research. We exemplify a mitochondrial DNA (mtDNA)-based strategy to trace the maternal geographic origins of M. fascicularis animals of unspecified origins. Macaca fascicularis of unspecified origins kept at primate research centers carry mtDNA haplotypes representing all three major genetic subdivisions. We suggest that the genetic background of study animals could be better specified in the future using an mtDNA-based approach, which would enable informed selection of study animals and help reduce variation within and among studies.

The Electrophysiology Analysis of Biological Conduit Sleeve Bridging Rhesus Monkey Median Nerve Injury with Small Gap

Based on the research on small gap bridging peripheral nerve injury in SD rats, we propose to investigate the possibility of bridging peripheral nerve injury with small gap using a de-acetyl chitin conduit in primates. The median nerves of 8 rhesus monkeys were cut at 2 cm above the elbow; the right sides were subjected to small gap (2 mm) bridging to repair the nerve with chitin conduit (conduit inner diameter 4 mm; length 10 mm); the left sides were subjected to traditionary epineurium suture. The electrophysiology analysis was conducted after the 3rd month and 6th month, respectively. The adhesions condition of biological conduit was only a little after the 15 3rd month; the conduit can remain cast contour; vessels can be seen on the conduit 16 surface and nerve intumescentia was not obvious. The adhesion and intumescentia condition can display better biocompatibilities than traditional suture methods. The motor nerve conduction velocity was only 1/2 of the control group. Although the motor nerve conduction velocity of the conduit group was a little higher than the epineurium suture group, there was no statistically significant difference (P>0.05) at the 3rd month (Table 1). The conduit cast contour disappeared after 6 months. The motor nerve conduction velocity was only 4/5 of the control group. The motor nerve conduction velocity of the conduit group was higher than the epineurium suture group; there were statistically significant differences (P<0.05) at 6 months. The nerve trunk conduction velocity of biological conduit was higher than the epineurium suture group at the 6th month, and there were statistically significant differences (P<0.05) (Table 2). The biocompatibility of the biological chitin conduit in primate rhesus monkeys was quite good. The electrophysiological results of biological conduit in primate rhesus monkeys were better than the traditional epineurium suture. The biological conduit can be used in primate rhesus monkeys to substitute for the traditional epineurium suture methods.

The anatomy and localization of the pedunculopontine nucleus determined using probabilistic diffusion tractagrophy

Deep brain stimulation (DBS) of the pedunculopontine nucleus (PPN) has recently been shown to effectively ameliorate medically intractable axial symptoms of Parkinson's disease (PD). The effects of DBS are not limited to the targeted structure, but will affect the distributed anatomical networks to which the target structure belongs. Therefore, understanding the anatomical connections of the PPN will help elucidate treatment effects. Furthermore, establishing the topography of cortical and sub-cortical connections of the PPN in the human brain could aid accurate targeting of critical pathways in DBS. This article summarizes the connections of the PPN and the distribution of these connections within this nucleus (topography) as previously determined using diffusion tensor imaging (DTI) in healthy human volunteers and in a primate Macaca mulatta brain. These findings highlight DTI as a useful tool for surgical targeting for DBS of the PPN, and also show that DTI can be used to accurately probe the anatomy of the human and monkey brain in vivo.

Chronic Alcohol Accentuates Nutritional, Metabolic, and Immune Alterations During Asymptomatic Simian Immunodeficiency Virus Infection

Alcohol abuse has been reported to have a high prevalence in the human immunodeficiency virus (HIV)-infected population. However, its impact on disease progression is unknown. Studies dissecting the drug-induced or alcohol-induced metabolic derangements that are likely to alter the course of disease progression are lacking. This is particularly important because of the substantial reduction in morbidity and mortality of patients on highly active antiretroviral therapy (HAART). HIV infection has become a more chronic disease during which alcohol-induced metabolic alterations may become more prevalent and pronounced. The present study used a model of chronic intragastric alcohol administration initiated 3 months before intravenous simian immunodeficiency (SIV) inoculation and continued thereafter throughout the course of SIV infection, to investigate the impact of chronic alcohol binge-like consumption during the initial 10-month asymptomatic phase of SIV infection in nonhuman primate rhesus macaques. Anthropometric, metabolic, biochemical, nutritional, and immune state indicators were examined before infection and at 3-month intervals in asymptomatic chronic alcohol-treated SIV-infected macaques and time-matched isocaloric and uninfected controls. Intravenous SIV(DeltaB670) infection resulted in increased viral load, decreased circulating CD4(+)/CD8(+) lymphocyte ratio, and increased lymphocyte proliferation (Ki67/CD3(+)). Chronic alcohol/SIV(+) animals showed a higher viral load at 3 months post-SIV infection as well as a significant and early decrease in caloric intake and nitrogen balance associated with a change in food choice. Rates of skeletal muscle protein synthesis and breakdown, mRNA expression of IGF-I, myostatin, or the ubiquitin ligase muscle atrophy F-box protein (MAFbx) did not differ from basal during the 10-month asymptomatic period of infection. However, muscle TNF-alpha mRNA expression was markedly increased at 10 months post-SIV infection in alcohol/SIV(+) animals. These findings suggest that chronic alcohol accelerates nutritional and metabolic dysregulation during SIV infection and may favor a skeletal muscle proinflammatory state, possibly conducive to subsequent muscle wasting.

353. Biological Comparison of Mesenchymal Stem Cells Derived from Bone Marrow and Adipose Tissue

The potential of adult mesenchymal stem cells (MSCs) to differentiate to diverse cell types in vitro and in vivo offers outstanding opportunities to use these cells as therapeutic agents. The biological characteristics of MSCs isolated from two distinct tissues, bone marrow and adipose tissue were evaluated in vitro and in vivo. MSCs derived from human and non-human primate (rhesus monkey) tissue sources were compared. The data indicate that MSCs isolated from rhesus bone marrow (rBMSCs) and human adipose tissue (hASCs) had more similar biologic properties than MSCs ofrhesus adipose tissue (rASCs) and human bone marrow MSCs (hBMSCs). Analyses of in vitro growth kinetics revealed shorter doubling time for rBMSCs and hASCs. rBMSCs and hASCs underwent significantly more population doublings than the other MSCs. MSCs from all sources showed a marked decrease in telomerase activity over extended culture; however they maintained their mean telomere length. All of the MSCs expressed embryonic stem cell markers, Oct-4, Rex-1 and Sox-2 for at least 10 passages. Early populations of MSCs types showed similar multilineage differentiation capability. However, only the rBMSCs and hASCs retain greater differentiation efficiency at higher passages. Overall in vitro characterization of MSCs from these two species and tissue sources revealed a high level of common biologic properties. The bone marrow and adipose tissue derived MSCs were then compared for the plasticity in vivo. In a time course study, the two types of MSCs were transplanted into the lateral ventricles of NIHIII immune deficient mice. The migration and engraftment of MSCs have been evaluated on 2, 4, and 6 weeks post engraftment. Our results indicated that while both cell types engrafted in multiple regions throughout the brain, the adipose tissue derived MSCs persisted in the brain for longer periods of time. The adipose tissue derived MSCs were detected up to six weeks post-transplantation. Since there is no ethical limitation on using adult stem cells, the results of this study suggest that adipose tissue and bone marrow will prove to be important sources of pluripotent stem cells.

Paternal mitochondrial DNA transmission during nonhuman primate nuclear transfer.

Offspring produced by nuclear transfer (NT) have identical nuclear DNA (nDNA). However, mitochondrial DNA (mtDNA) inheritance could vary considerably. In sheep, homoplasmy is maintained since mtDNA is transmitted from the oocyte (recipient) only. In contrast, cattle are heteroplasmic, harboring a predominance of recipient mtDNA along with varying levels of donor mtDNA. We show that the two nonhuman primate Macaca mulatta offspring born by NT have mtDNA from three sources: (1) maternal mtDNA from the recipient egg, (2) maternal mtDNA from the egg contributing to the donor blastomere, and (3) paternal mtDNA from the sperm that fertilized the egg from which the donor blastomere was isolated. The introduction of foreign mtDNA into reconstructed recipient eggs has also been demonstrated in mice through pronuclear injection and in humans through cytoplasmic transfer. The mitochondrial triplasmy following M. mulatta NT reported here forces concerns regarding the parental origins of mtDNA in clinically reconstructed eggs. In addition, mtDNA heteroplasmy might result in the embryonic stem cell lines generated for experimental and therapeutic purposes ("therapeutic cloning").

708. Retroviral Vector Integration into the Genome of Rhesus Macaque Long-Term Repopulating Cells

Replication defective retroviruses are very attractive tools for hematopoietic stem cell (HSC) gene therapy largely because of their ability to integrate into genomic DNA. While the risk of insertional mutagenesis has long been recognized, reports of neoplasia consecutive to proto-oncogenes' activation in mice and humans have refocused attention on the safety limitations of these vectors. Mapping studies of retroviral integration sites (RIS) in human cell lines have suggested that retroviral vectors favor integration near transcriptional start sites. Medical applications using these vectors are aimed at HSC, and thus large-scale analysis of RIS in a relevant pre-clinical situation is essential to assess the safety of HSC gene therapy. Here we report the mapping of 423 RIS in a long-term model of autologous retrovirally-transduced HSC transplantation in the non-human primate (Macaca mulatta). Circulating granulocytes and mononuclear cells from 22 rhesus macaques, transplanted with G-CSF + SCF mobilized CD34+ peripheral blood stem cells transduced with an amphotropic Moloney murine leukemia-derived vector containing a neomycin-resistance marker gene, have been analyzed between one and five years after transplantation. Genomic regions adjacent to RIS have been retrieved using linear amplification-mediated PCR followed by shotgun TA cloning, and mapped to the NCBI build 34 of the human genome sequence. Out of the 423 RIS retrieved, 37% landed between the transcriptional start and stop codons of a member of the well-defined RefSeq set of genes, 55% were located in non-coding regions of the genome and 8% were found to be in interspersed repeats and therefore not mappable. Analysis of the targeted genomic regions provides evidence for non-random insertion: 8 independent RIS, recovered from 6 animals, have been mapped within the 2 first introns of the myelodysplasia syndrome 1 gene (MDS1), and seven other genes have 2 independent insertions. Among these 8 genes, it is noteworthy that three are known to be involved in chromosomal rearrangements observed in spontaneous acute human leukemias: the proto-oncogene runt-related transcription factor 1 (RUNX1), the fms-related tyrosine kinase 3 (FLT3) and MDS1. The presence of the fusion sequence between the genomic MDS1 region and the 5'-LTR of the vector has been confirmed using insertion-specific primers for 6 out of the 8 events, and clonal evolution as well as expression of the targeted gene are being analyzed. These observations suggest that retroviral integration in long-term repopulating HSC is highly non-random and is favored at specific loci. Systematic mapping of RIS after HSC gene transfer in the non-human primate will provide critical pre-clinical data necessary for risk assessment of such vectors, and offers also a powerful means for identifying genes involved in the biology of HSC.

490. Long Term Expression and Biodistribution of HIV Vector Pseudotyped with Deletion Mutant of the Ebola Envelope Glycoprotein Following Instillation in Airway of Nonhuman Primates

Several studies have demonstrated that pseudotyping lentiviral vectors with other viral envelopes can optimize and even alter the tropism to cell types known to be non-permissive to VSV-G-HIV mediated transduction. We and others have demonstrated that HIV vector pseudotyped with the Ebola Zaire (EboZ-GP) envelope can transduce the airway epithelia of immunocompetent C57BL/6 mice through the apical surface of the cells. A group of EboZ-GP envelope deletion mutants was generated to minimize EboZ-GP associated toxicity and perhaps improve vector-mediated transduction. Both reduced cellular toxicity and significant improvement in transduction efficiency has been shown in vitro and in vivo with these deletion mutants. HIV-based vectors pseudotyped with the Non-Toxic EboZ-GP Deletion 4 or 6 (NTD4 or NTD6) and encoding for the b-galactosidase reporter gene were evaluated following instillation in the lung of nonhuman primates (rhesus macaques) and compared to the wild-type EboZ-GP envelope pseudotyped HIV vector. Transduction efficiency was assessed by b-gal. staining and TaqMan PCR 8 to 10 weeks post-administration. In addition, a biodistribution analysis was performed to determine whether HIV vector could leak into other internal organs following lung instillation. TaqMan PCR was used to analyze different organs such as spleen, liver, gonads and brain for the presence of HIV vector genome copies. Results indicate that HIV-based vector pseudotyped with the Non-Toxic EboZ-GP deletion mutant transduces airway epithelia and submucosal glands more efficiently than the wild type EboZ-GP pseudotyped vector. Areas of the transduced lung with pseudotyped HIV vector showed sections with up to 18% of b-gal. positive cells by histochemical staining. The instilled lung contained up to an average of 21 HIV vector genome copies per 100 total lung cells as determined by TaqMan PCR. Overall, this study shows that deletion mutants of the Ebola envelope are less toxic and that in the context of HIV-based vector, transduction efficiency of nonhuman primate airway is improved.

Liver regeneration investigated in a non-human primate model ( Macaca mulatta)

Background/Aims: An adequate model to study liver regeneration in humans is presently unavailable. We explored the feasibility of studying liver regeneration in a genetically similar species to man, the non-human primate Rhesus macaque. Methods: Five animals were studied; two underwent 60% hepatectomy, one underwent 30% hepatectomy, and cholecystectomy alone was performed on two animals. Laparoscopic-guided or open liver biopsies were performed on days 1, 2, 7, 14, 21, 30 and 60 following all surgeries. Liver regeneration was evaluated by measuring Ki-67, proliferating cell nuclear antigen expression and mitotic index, calculating changes in the surface area of the liver remnant and assessing intrahepatic production of cytokines. Results: Significant liver regeneration was induced in the animals that underwent 60% hepatectomy, peaking between days 21–30 postoperatively. Regeneration was minimal in all other animals studied. Cytokine production followed a similar pattern. Maximal liver regeneration correlated with restoration of surface area in the liver remnant. Conclusions: Sixty percent hepatectomy in a non-human primate model induced significant liver regeneration, maximizing 21–30 days following partial hepatectomy, suggesting a significant interspecies difference when compared to a rodent hepatectomy model. A partial hepatectomy model in Rhesus macaques may allow further characterization of liver regeneration in a species closer to humans.

Telomere Biology and Cellular Aging in Nonhuman Primate Cells

To determine how cellular aging is conserved among primates, we analyzed the replicative potential and telomere shortening in skin fibroblasts of anthropoids and prosimians. The average telomere length of the New World primates Ateles geoffroyi (spider monkey) and Saimiri sciureus (squirrel monkey) and the Old World primates Macaca mulatta (rhesus monkey), Pongo pygmaeus (orangutan), and Pan paniscus (pigmy chimpanzee) ranged from 4 to 16 kb. We found that telomere shortening limits the replicative capacity of anthropoid fibroblasts and that the expression of human telomerase produced telomere elongation and the extension of their in vitro life span. In contrast the prosimian Lemur catta (ring-tailed lemur) had both long and short telomeres and telomere shortening did not provide an absolute barrier to immortalization. Following a transient growth arrest a subset of cells showing a reduced number of chromosomes overgrew the cultures without activation of telomerase. Here we show that the presence of continuous TTAGGG repeats at telomeres and rigorous control of replicative aging by telomere shortening appear to be conserved among anthropoid primates but is less effective in prosimian lemurs.

Yohimbine increases the binding potential for [11C]flumazenil in the monkey brain.

We evaluated the impact of yohimbine administration on benzodiazepine (BDZ) receptor binding in the central nervous system of non-human primates (rhesus monkeys). Estimates of the binding potential (Bmax/Kd) of BDZ receptors were made following intravenous administration of yohimbine, an alpha2-adrenoceptor antagonist. Positron emission tomography was used in conjunction with [11C]flumazenil (Ro 15-1788), a tracer for central BDZ receptor binding activity. The effects of yohimbine were compared with a control condition in which saline was administered. Yohimbine significantly increased the binding potential in the hippocampus, as assessed using a Student's t-test with Bonferroni correction. The result that the administration of yohimbine readily induces an increase in the binding potential for BDZ receptors in the primate brain suggests that the presence of an anxiety state potentiates the effect of anxiolytics.

Interphotoreceptor Matrix in the Fovea and Peripheral Retina of the Primate Macaca mulatta: Distribution and Glycoforms of SPACR and SPACRCAN

SPACR and SPACRCAN localization in the interphotoreceptor matrix (IPM) of the fovea and peripheral retina of Macaca mulatta was established with antibodies to these core proteins and the chondroitin sulfate epitopes and lectin binding properties of these molecules were defined. The IPM of both rods and cones labeled with anti-SPACR, anti-SPACRCAN, anti-ΔDi6S antibodies and wheat germ agglutinin (WGA). Whereas anti-SPACR and anti-SPACRCAN antibodies labeled rod and cone matrix compartments with similar intensity, the ΔDi6S chondroitin antibody labeling was more intense around cones than rods. Peanut lectin (PNA) labeling was present only around cones. No IPM labeling was observed with ΔDi0S-chondroitin or ΔDi4S-chondroitin antibodies. Western blots of undigested IPM extracts showed anti-SPACR immunoreactivity at 150kDa, colocalizing with the position of WGA and PNA binding. In Western blots of the chondroitinase ABC digested sample and samples double digested with chondroitinase ABC and AC II, anti-SPACR immunoreactivity, WGA and PNA labeling intensity were virtually identical to that in the undigested sample, with prominent staining of the 150kDa SPACR band. In contrast, anti-SPACRCAN immunoreactivity was not present in the undigested sample, but was evident in both the chondroitinase ABC and double digested samples as a broad band at approximately 230kDa. ΔDi6S, ΔDi4S, WGA and PNA labeling colocalized with the anti-SPACRCAN immunoreactivity in the chondroitinase ABC digested sample. These findings indicate that SPACR and SPACRCAN are present around cones in the fovea and both rods and cones in the peripheral retina, but that the specific glycoforms of these molecules are different depending on whether present in the cone or rod associated IPM.

Long-term effects of X-irradiation on gastrointestinal function and regulatory peptides in monkeys

Purpose: To investigate the long-term effects of X-irradiation on different aspects of gastrointestinal function in the non-human primate (Macaca mulatta). Materials and methods: Animals were exposed to X-radiation (5 or 6 Gy) or not (sham) and gastrointestinal function was investigated 4-6 years after exposure. Basal and agonist-stimulated short circuit current (Isc) responses were measured in isolated jejunum. Intestinal tissue was taken for histological analysis as well as for determination of mucosal marker enzyme activities and gastrointestinal regulatory peptide levels. Vasoactive intestinal peptide receptor characteristics were determined as well as VIP-stimulated Isc responses. GI peptides were also measured in plasma. Results: Few differences were seen in basal electrical parameters or tissue morphology but there was a tendency for reduced basolateral membrane enzyme activity. VIP-stimulated Isc responses were reduced in irradiated animals as were VIPstimulated adenylate cyclase responses. Plasma and tissue (ileal and colonic muscle layers) gastrin releasing peptide levels were increased in irradiated animals. In contrast circulating gastrin levels were lower. Conclusions: Late effects of total-body irradiation on GI function in monkeys showed altered circulating and tissue levels of some GI peptides. In addition the biological effects of vasoactive intestinal peptide were modified.

Estimation of the duration of the cycle of the seminiferous epithelium in the non-human primate Macaca mulatta using the 5-bromodeoxyuridine technique.

A comparatively low yield of germ cells has been reported for the spermatogenic process in primates. Kinetic studies of spermatogenesis and the spermatogenic cycle are needed to investigate this phenomenon but require the application of radioactively labeled compounds or irradiation. We have therefore investigated the suitability of a non-radioactive approach, viz., administration of 5-bromodeoxyuridine, for the determination of the kinetics of the spermatogenic cycle in a non-human primate, the rhesus monkey (Macaca mulatta). Four adult in-season animals received a bolus of 33 mg/kg 5-bromodeoxyuridine, one testis from each monkey was removed 3 h later and the other testis after 10 days and 11 h. Tissue was fixed in Bouin's solution and embedded in Paraplast. 5-Bromodeoxyuridine was localized by immunogold-silver staining with a monoclonal antibody. PAS-hematoxylin counterstaining was used for spermatogenic stage identification. At 3 h, the leptotene and zygotene spermatocytes in stages VII-IX were the most advanced 5-bromodeoxyuridine-positive cells. At 10 days 11 h, the label had advanced and pachytene spermatocytes in stages VI-IX contained 5-bromodeoxyuridine. The duration of the spermatogenic cycle was 10.42+/-0.07 days (range: 10.25-10.62 days). Peritubular cells and interstitial cells were rarely 5-bromodeoxyuridine-positive, and Sertoli cells were consistently negative for 5-bromodeoxyuridine. Importantly, our kinetic data closely resemble those obtained by means of the application of irradiation for this macaque species. We conclude that administration of 5-bromodeoxyuridine represents a non-radioactive reliable approach for studying kinetic aspects of the spermatogenic process in primates.

Iron and virulence of Haemophilus ducreyi in a primate model.

The pathogenesis of chancroid is currently unclear. There are discrepancies between the virulence of Haemophilus ducreyi in the human and animal experiments. Iron availability influences the virulence of many pathogens. The objective of this study was to investigate the role of iron in virulence of H. ducreyi. Intradermal inoculation of the primate Macaca mulatta was studied as an animal model for pathogenesis of chancroid. This model then was used to study the influence of iron availability on virulence of H. ducreyi. Eleven strains of H. ducreyi with proven avirulence in the rabbit intradermal test and one virulent control strain were used. Two of the strains had been shown to cause ulcers in a human inoculation experiment. Strains were suspended in fluid with different iron compounds before intradermal injection. Other monkeys were treated with injectable iron before inoculation with bacteria suspended. All but one of the test strains produced a chancroid-like ulcer from which H. ducreyi could be isolated. The minimal ulcerative dose was 10(5) cfu. Iron in the injection fluid decreased this dose 10-fold. In animals pretreated with intramuscular iron, the minimal ulcerative dose decreased to 10(4) cfu and all eleven strains became ulcerative. The availability of iron increases virulence of H. ducreyi. The iron pretreated primate model is useful for the study of virulence factors of H. ducreyi because of its ability to produce lesions with strains that avirulent in other animal models but pathogenic to humans.

Histamine‐immunoreactive neurons and their innervation of visual regions in the cortex, tectum, and thalamus in the primate Macaca mulatta

The histaminergic system is involved in the control of arousal in the brain and may impact significantly on visual processing. However, little is known about the histaminergic innervation of visual areas, or the histamine system in the primate brain, in general. We examined in Macaca mulatta the location of histamine-immunoreactive neurons and the innervation of important cortical and subcortical visual areas by histamine-immunoreactive axons. Brain sections were treated with an antibody to histamine and processed with standard immunohistological procedures. Histamine-immunoreactive neurons (20–45 μm in diameter) were localized bilaterally in the hypothalamus, particularly in ventral, lateral, posterior, and perimammillary hypothalamic areas. These hypothalamic cells appear to provide the sole neural source of histamine in the macaque brain. A plexus of varicose histamine-immunoreactive axons was present throughout the superior colliculus, the dorsal and ventral lateral geniculate nuclei of the thalamus, the reticular nucleus of the thalamus, the lateral posterior/pulvinar complex, and the visual cortex, including areas 17, 18, and the nearby extrastriate cortex. The axons nearly homogeneously innervated every region and layer in these structures, except for an increase in density in layer 1 of the visual cortex and in the superficial-most layers of the superior colliculus. Histaminergic axons broadly innervated every visual region examined. In comparison with the other aminergic and the cholinergic projection systems, which show considerable projection specificity, the histaminergic projection exhibited great homogeneity. The breadth of the distribution of histaminergic axons ensures that virtually all levels of visual processing in the primate can be influenced, either directly or indirectly, by the neuromodulatory effects of histamine. © 1996 Wiley-Liss, Inc.

Histamine-immunoreactive neurons and their innervation of visual regions in the cortex, tectum, and thalamus in the primate Macaca mulatta.

The histaminergic system is involved in the control of arousal in the brain and may impact significantly on visual processing. However, little is known about the histaminergic innervation of visual areas, or the histamine system in the primate brain, in general. We examined in Macaca mulatta the location of histamine-immunoreactive neurons and the innervation of important cortical and subcortical visual areas by histamine-immunoreactive axons. Brain sections were treated with an antibody to histamine and processed with standard immunohistological procedures. Histamine-immunoreactive neurons (20-45 microns in diameter) were localized bilaterally in the hypothalamus, particularly in ventral, lateral, posterior, and perimammillary hypothalamic areas. These hypothalamic cells appear to provide the sole neural source of histamine in the macaque brain. A plexus of varicose histamine-immunoreactive axons was present throughout the superior colliculus, the dorsal and ventral lateral geniculate nuclei of the thalamus, the reticular nucleus of the thalamus, the lateral posterior/pulvinar complex, and the visual cortex, including areas 17, 18, and the nearby extrastriate cortex. The axons nearly homogeneously innervated every region and layer in these structures, except for an increase in density in layer 1 of the visual cortex and in the superficial-most layers of the superior colliculus. Histaminergic axons broadly innervated every visual region examined. In comparison with the other aminergic and the cholinergic projection systems, which show considerable projection specificity, the histaminergic projection exhibited great homogeneity. The breadth of the distribution of histaminergic axons ensures that virtually all levels of visual processing in the primate can be influenced, either directly or indirectly, by the neuromodulatory effects of histamine.

Endocrine control of testicular somatic and premeiotic germ cell development in the immature testis of the primate Macaca mulatta

Four groups(N = 3 per group) of juvenile rhesus monkeys (Macaca mulatta, 14-20 months old) received either vehicle or highly purified human follicle-stimulating hormone (FSH; 10 IU kg-1 day-1), human chorionic gonadotropin (hCG; 250 IU every alternate day) or both hormones for a period of 4 weeks. Testicular volume and weight increased more than twofold after single and more than sixfold after combined hormone treatment. Serum and intratesticular testosterone were at supraphysiological levels in hCG-treated animals and rose even more after combined treatment; a minor elevation of intratesticular testosterone was also observed after FSH treatment. Serum inhibin was elevated after hCG or FSH treatment and increased more than twofold during the first 3 weeks of combined treatment. Semiquantitative analysis of cell numbers showed a statistically non-significant increase in Sertoli cells and Ad- and Ap-spermatogonia after single hormone treatment. Combined treatment induced a further increase in the number of spermatogonia. Leydig cells were only encountered after hCG treatment; their number was more than threefold higher after combined treatment compared with hCG alone. Follicle-stimulating hormone stimulated Sertoli cell and Ap spermatogonia proliferation but did not induce morphological differentiation of Sertoli cells, peritubular cells or Leydig cells. Human CG treatment, however, induced Sertoli cell proliferation and morphological differentiation. It had effects on spermatogonial proliferation but induced differentiation of peritubular cells. Combined treatment initiated the greatest morphological and functional differentiation of Sertoli cells, peritubular cells, Leydig cells and spermatogonia. Flow cytometric analysis confirms an increase of mitotically active cells. The observations show that FSH and testosterone can induce Sertoli cell proliferation. Morphological differentiation of Sertoli cells may be mediated indirectly by environmental and paracrine stimuli released from peritubular cells, whose differentiation is androgen dependent. Leydig cells are stimulated mainly by hCG. Our present and previous data lead us to propose that FSH contributes to the final number and activity of Leydig cells, which secrete immunoreactive inhibin in response to hCG.(ABSTRACT TRUNCATED AT 400 WORDS)

Response to hemorrhagic stress in the rhesus monkey fetus in utero: effects on the pituitary-adrenal axis.

In human pregnancy, fetoplacental hemorrhage is often associated with morbidity and potentially mortality. We investigated the effect of acute fetal hemorrhage on the fetal pituitary-adrenal axis in the subhuman primate (Macaca mulatta). We measured fetal and maternal plasma concentrations of ACTH, cortisol, and dehydroepiandrosterone sulfate (DHAS) by RIA in 10 rhesus monkeys. At 133-158 days of gestation (d) the fetuses were subjected to acute hemorrhage (0.5 mL/min for 10 min). Fetal plasma ACTH and cortisol concentrations were significantly increased above baseline in response to fetal hemorrhage. There was a more rapid, but significantly reduced, fetal plasma ACTH and cortisol response in the 133-143 d fetuses than in the 147-158 d fetuses. In 133-143 d fetuses, the maximal changes from baseline in plasma ACTH and cortisol concentrations were +6.5 +/- 2.6 pmol/L at +25 min and +4.55 +/- 1.19 nmol/L at +10 min, respectively. Fetal plasma ACTH and cortisol concentrations remained elevated throughout the 60-min period after hemorrhage (3.06 +/- 1.21 pmol/L and +2.42 +/- 1.05 nmol/L at +70 min). In 147-158 d fetuses, the maximal changes from baseline in plasma ACTH and cortisol concentrations were +13.7 +/- 4.23 pmol/L and +12.92 +/- 3.25 nmol/L at +70 min. In the 133-143 d fetuses, plasma DHAS concentrations did not change in response to hemorrhage, whereas in the 147-158 d fetuses, plasma DHAS concentrations were elevated above baseline during the hemorrhage (+624.2 +/- 269.5 nmol/L, at +9 min) and returned quickly to pre-hemorrhage values. These data suggest that the fetal pituitary-adrenal axis plays a role in the fetal response to intrauterine stress, but that only later in gestation is the fetal cortisol response to fetal hemorrhage mediated via ACTH secreted by the fetal pituitary.

Responses of cultured adult monkey trigeminal ganglion neurons to capsaicin

The sensitivity of adult primate (Macaca mulatta) trigeminal ganglion neurons to capsaicin was studied using whole-cell recording techniques. Neurons responding to capsaicin (9 out of 14) generated inward currents of up to 3.0 nA (median = 0.23 nA; interquartile range = 1.19 nA) upon drug application measured at -60 mV. Capsaicin-sensitive neurons had longer action potential (AP) durations than capsaicin-insensitive neurons.