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At least 19 recordsLinked to original sources
PubMed1989

N-methyl-D-aspartate receptors in the cortex and hippocampus of baboon (Papio anubis and Papio papio).

In vitro autoradiography was used to examine the N-methyl-D-aspartate receptor in the brain of a baboon species, Papio anubis, and compared to that of Papio papio which exhibits a photosensitive epilepsy. The epilepsy originates in the frontal cortex and is accompanied by an enhanced sensitivity to N-methyl-D-aspartate. In both Papio anubis and Papio papio, the density of N-methyl-D-aspartate receptors was greatest in the hippocampus, followed by associational areas including frontal cortex, and low in primary sensory areas such as the visual cortex. The receptors were concentrated in the outer cortical layers I-III, very low in layer IV except in primary visual cortex, and of intermediate density in layer V. The density of binding sites was approximately two-fold lower than previously observed in the rodent brain, whereas the affinity of the receptor for [3H]L-glutamate was greater in the primate versus the rodent brain. Glycine potentiated the binding of [3H]L-glutamate in both cortex and hippocampus. No significant differences in the properties of N-methyl-D-aspartate receptors were observed between the two baboon species, suggesting that the photosensitivity of Papio papio is not due to alterations in the binding of L-glutamate to the N-methyl-D-aspartate receptor complex.

Animals↗
PubMed1991

Infectivity of Trypanosoma (Trypanozoon) brucei gambiense for baboons (Papio hamadryas, Papio papio).

In order to study sensitivity or resistance of T.b. gambiense to baboon serum, two species of baboons, P. hamadryas and P. papio were inoculated with T.b. gambiense clone LiTat 1.1. Both species were receptive to infection but, parasitological and immunological parameters showed that P. papio was more trypanotolerant than P. hamadryas. The VAT-specific trypanolysis test and the ELISA, using MoAb for circulating antigen detection may be appropriate for the diagnosis of human trypanosomiasis due to T.b. gambiense.

Animals↗
PubMed1989

Demonstration of GABA immunoreactive cells in the inferior olive of baboons (Papio papio and Papio anubis).

The distribution of gamma-aminobutyric acid (GABA)-like immunoreactivity was studied in semithin sections through the inferior olivary complex in two baboon species. About 5% of the olivary neurons were GABA-immunoreactive. The GABA-immunoreactive neurons differed from the large majority of olivary neurons by their smaller size and their lower contents of aspartate, as judged by analysis of alternate sections labelled with an aspartate antiserum. The present observations raise the possibility that in primates the GABAergic modulation of the activity of the climbing fibre system is effected not only by the previously described input from the cerebellar nuclei and other extrinsic sources, but that intrinsic neurons also participate.

Animals↗
PubMedDate not supplied

Relationships between benzodiazepine receptors, impairment of GABAergic transmission and convulsant activity of beta-CCM: a PET study in the baboon Papio papio.

Central type benzodiazepine receptors were studied in vivo by positron emission tomography in brain areas of 2 different groups of the baboon Papio papio: non-photosensitive (group 1) and those with an allylglycine-induced decrease in GABA-mediated inhibition (group 2). Further, a naturally photosensitive Papio papio (+3 level of photosensitive response) was compared to both groups. Regional brain binding of the specific benzodiazepine receptor ligand, [11C]Ro 15-1788, was not significantly different between groups 1 and 2. In addition, the data from the naturally photosensitive Papio papio did not seem to differ markedly from groups 1 and 2 either. Pharmacological effects of increasing doses of beta-CCM (0.05-3 mg/kg i.v.) and regional benzodiazepine receptor occupancy by the drug were simultaneously studied using electroencephalographic activity recording and positron emission tomography. A positive correlation was observed between the degree of photosensitivity of the baboon and sensitivity to the action of beta-CCM, with increasing convulsant efficacy of beta-CCM in going from group 1 to the naturally photosensitive baboon, then to group 2. Dose-related displacement curves of [11C]Ro 15-1788 binding by beta-CCM revealed that reduction in brain GABA concentration did not modify the inhibitory potency of beta-CCM on [11C]Ro 15-1788 binding in cerebral cortex. This suggests a lack of detectable in vivo allosteric effects of GABA on beta-CCM binding during beta-CCM-induced seizures. Thus, a given dose of beta-CCM displayed increasing pharmacological potency in going from baboons with the lowest photosensitivity to those with the highest, whereas benzodiazepine receptor occupancy by beta-CCM was similar in the cerebral cortex of the different baboons. Conversely, a given level of convulsant activity of beta-CCM was related to a different benzodiazepine receptor occupancy by the drug, depending on the photosensitivity of Papio papio. A given dose of a drug may, thus, have a different pharmacological potency when occupying the same number of receptors, depending on the physiopathological state of the subject.

Animals↗
PubMed1975

[Evolution of visual evoked responses during various states of vigilance in Papio papio (author's transl)].

Averaged evoked responses (AER) to light flashes were recorded in baboons (Papio papio) during wakefulness, slow-wave sleep and rapid eye movement (REM) periods, at the visual cortex, retrocalcarine sulcus, optic tract (OT), lateral geniculate (LG) and pulvinar. Waking AERs were composed: in the OT, of a negative, low amplitude wave at 13.3 msec (I), a high amplitude wave at 34.8 msec (II), a negative wave at 72 msec (III) and a late component at 151 msec; in the LG, a small positive wave (II) with a peak latency of 40 msec, a high amplitude negative wave (III) with a latency of 70 msec and a late component; in the pulvinar of two low amplitude short latency waves (I and II), respectively negative and positive at 25 msec and 40 msec, then a high amplitude negative wave (III) at 75 msec and a late component; in the retrocalcarine sulcus 3 positive waves (I, II and III) were recorded at 25, 45 and 100 msec and a late component; in the visual cortex, 3 low amplitude negative waves (II, III and IV at 40, 50 and 54 msec, then a positive wave at 80 msec and some late components. In slow-wave sleep, AERs did not change in the OT, but in the LG and pulvinar, they showed an increase in the amplitude of wave II from stage 1 to stage 3. At the cortical level, early waves (II for the retrocalcarine sulcus, II and IV for the visual cortex) presented a marked increase in amplitude during stages 2 and 3, but only a slight increase for stage 1. Peak latency increase of each wave in cortical and subcortical AERs was seen during slow-wave sleep. REM AERs resembled, in amplitude and peak latency, those recorded in the LG and pulvinar during wakefulness; in the visual cortex and retrocalcarine sulcus, they were similar to those obtained during wakefulness and stage 1. In conclusion, a different evoked response was found between visual cortex and deep structures (except for the OT): firstly, during slow-wave sleep (the AERs showed a difference for stage 1 between the visual cortex or the retrocalcarine sulcus and the LG or the pulvinar), secondly, in REM (on the cortex, REM AERs looked like wakefulness and stage 1 responses); on the contrary, in the LG and pulvinar, REM AERs were similar only to those recorded during waking. Finally, it can be said that for Papio papio the differentiation and structural responses between the various stages of sleep (particularly light sleep and REM) were greater in the cortex than in the thalamic structures.

Animals↗
PubMed1979

The influence of cortisone on EEG and seizure activity in the baboon Papio papio.

The ability of cortisone to modify EEG and seizure activity was investigated in the baboon, Papio papio. Acute intramuscular doses (0.5-4 mg/kg) caused a dose-dependent increase in seizure response to a flashing light stimulus. This increase in seizure response was apparent in both seizure duration and the spread of convulsive activity. Along with enhancement of seizures, cortisone was found to cause marked changes in the EEG, ranging from the appearance of interictal paroxysmal activity to alterations in spectral characteristics of the wave forms. Increases in slow waves appeared concomitant with a decrease in fast activity in the 18-25 c/sec range. Since previous studies have indicated that seizure proclivity in the Papio papio is maximal at the time of the day when cortisol excretion rates peak, these findings lend further evidence to the idea that corticosteroids may be involved in the thythmic variation of seizure activity in the baboon.

Animals↗
PubMed1981

Cortical unit activity during intermittent photic stimulation in Papio papio. Relationship with paroxysmal fronto-rolandic activity.

Extracellular records have been made in the fronto-rolandic (FR), parietal and occipital cortical areas in Papio papio injected with allylglycine and paralysed with a synthetic curarizing agent. The organization of the unit discharges in the absence of intermittent light stimulation (ILS) is normal. During ILS, unit discharges in the FR cortex are organized in bursts of high frequency that are synchronous with the spikes of the EEG paroxysmal discharges (PD) in the same territory; this burst-organized FR activity is reversible, and bursts disappear when the ILS stops. In addition, in the FR cortex, triple or single flashes induced paroxysmal visual evoked potentials (PVEP) whose spikes were accompanied by bursts identical to the preceding ones. The slow waves which constituted the PD and the PVEP corresponded to a transitory inhibition of the FR neuronal activity. From the unit discharge patterns, no difference was observed between the two EEG paroxysmal activities recorded. No pattern of discharge in bursts was ever observed in the parietal and occipital cortex. The synchronizing role of the light stimulation in the FR cortex in Papio papio under allylglycine is discussed and the results are used to compare the experimental model with the naturally highly photosensitive animal. The particular reactivity of the FR cortex with respect to other regions is also discussed. Finally, the results bring forth new information in favour of a similarity between PD and PVEP.

Animals↗
PubMedDate not supplied

Reciprocal inhibition between seizures induced by intermittent light stimulation and premotor cortical stimulation in Senegalese baboons, Papio papio.

The temporal relationship between the degree of photosensitivity and the intensity of kindling stimulus response was examined in four Senegalese baboons, Papio papio, kindled at the premotor cortical area. When fully kindled, the intensity of photosensitivity diminished significantly in all the animals. With successive daily intermittent light stimulation, two animals showed partial recovery and the other two showed complete recovery to the prekindling level of photosensitivity. When premotor cortical kindling stimulation was subsequently reapplied, three-quarters of the animals failed to respond with kindled seizures and additional stimulations were necessary to reestablish kindled seizure. Two of these three animals also required increased stimulus intensity before the previously established generalized seizure threshold could be reinstated. The frontorolandic cortex is known as the most epileptogenic area in photosensitive Papio papio. In this species, spontaneous generalized convulsive seizures, intermittent light stimulation-induced seizures, and kindled generalized convulsive seizures are all known to share a common electroclinical phenomenology. The reciprocal inhibition observed in this study between generalized seizures induced by either intermittent light stimulation or by premotor cortical kindling stimulation further strengthens the possibility that they also share a common neuronal mechanism.

Animals↗
PubMed1979

Comparison of the karyotypes of four Cercopithecoidae: Papio papio, P. anubis, Macaca mulatta, and M. fascicularis.

The karyotypes of two species of baboons, Papio papio and P. anubis, and of two species of Macaca, M. mulatta and M. fascicularis, are compared after the use of numerous banding techniques. No difference was detected between the karyotype of the two Papio species. However, a minor change in the T-staining of a short segment, probably heterochromatic, could be detected between the Papio species and M. mulatta. A paracentric inversion exists between these three and M. fascicularis. These karyotypes are briefly compared with those of the Pongidae and man. The value of the karyotypic criteria and of the methods used for taxonomy is discussed.

Animals↗
PubMed1990

Quantitative evaluation of benzodiazepine receptors in live Papio papio baboons using positron emission tomography.

The binding of the 11C-labeled benzodiazepine antagonist Ro 15-1788 (flumazenil) was measured in the neocortex of live Papio papio baboons by positron emission tomography. This allowed us to calculate in vivo (i.e., at physiological temperature, neurotransmitters concentrations, and ionic environment) the apparent density of available benzodiazepine receptors (B'max) and the dissociation constant of Ro 15-1788 (Kd). By coadministering increasing doses of unlabeled Ro 15-1788 with [11C]Ro 15-1788 and assuming that nonsaturable radioactivity indicated the free ligand concentration, we were able to obtain saturation isotherms. We showed that a state of quasiequilibrium was reached 50 min after the administration of the radioligand. Linear Scatchard plots allowed us to calculate B'max at 78 and 50 pmol/ml of cerebral tissue in the occipital and frontal cortices, respectively. In both these areas, Kd is on the order of 6 nM, with a Hill number very close to unity. This indicates that Ro 15-1788 binds in vivo with high affinity to an homogeneous population of saturable sites. A similar measurement was carried out on a naturally photosensitive P. papio baboon. Absolute values of B'max, Kd, and Hill number were similar to those of the control baboons. Although results concerning this baboon can only be considered as a case report, this similarity may suggest that its epileptic syndrome is not related to a large change in B'max or Kd, at least in occipital and frontal cortices. Our results showed that quantitative estimation by positron emission tomography of some characteristics of benzodiazepine receptors is possible in live baboons and may represent a supplementary tool for investigating further the molecular mechanisms of benzodiazepine receptor function in physiological and physiopathological conditions. We suggest that a similar method of quantification of classic in vivo [3H]Ro 15-1788 binding could be usefully adapted when studying rodent models of epilepsy, stress, and other neuropsychological disorders. On the other hand, the similarity between the B'max and Kd values we obtained in baboons and those recently reported in humans using similar methods emphasizes that most of the in vivo characteristics of the benzodiazepine receptors of baboons are very close to those of human benzodiazepine receptors. This confirms that P. papio baboons are a suitable animal model for studying the pharmacology of benzodiazepine receptor ligands before clinical applications in humans.

Animals↗
PubMed1990

[Value of the monkey Papio papio for the study of epilepsy].

The baboon Papio papio is the only animal model showing a natural photosensitive epilepsy very similar to that observed in some human epileptic patients. In the baboon, intermittent light stimulation (ILS) induces bilateral and synchronous myoclonic twitches which are associated with paroxysmal discharges (PDs) predominating in the frontal cortex, and can be followed by generalized tonic-clonic seizures. We were able to demonstrate the motor cortical origin of all these manifestations since neuronal generators responsible for paroxysmal discharges are localized there and are activated by visual afferents from the occipital lobe. The corpus callosum is the structure determining the interhemispheric synchronization of PDs. An unbalance of neurotransmitter systems such as GABA or excitatory amino acids should be responsible for the hereditary predisposition of baboons to photosensitive epilepsy. Some Papio papio, either photosensitive or not, may show spontaneous truncular myoclonic twitches, different from those induced by intermittent light stimulation, and resembling the intention myoclonus as observed in some human neurological disorders (post-anoxic syndrome, degenerative encephalopathies such as Ramsay-Hunt syndrome...). Because of the absence of any abnormal electrographic discharge, this myoclonus is considered non epileptic. Until now, we were unable to determine the structure generating this myoclonus. The most probable origin is in the lower brain stem. Experimental data suggest that a local unbalance of the cholinergic neurotransmission could be responsible for the predisposition of baboons to show this type of myoclonus.

Animals↗
PubMed1976

Spontaneous recurrent seizure state induced by daily electric amygdaloid stimulation in Senegalese baboons (Papio papio).

Daily electrical stimulation of the amygdala in Senegalese baboons (Papio papio) resulted in the development of generalized convulsive seizures focal onset through five distinct clinical stages in an average of 72 days. The chronologic pattern of electroclinical features suggested that vertical intrahemispheric ictal dissemination was of primary importance in the progressive seizure development. Some animals developed spontaneous recurrence of both partial complex and primary generalized seizures. The kindling preparation in P. papio represents a unique model of human epilepsy with its secondary generalized convulsive seizure development, spontaneously recurrent partial and primary generalized seizures in the background of predisposed epileptogenic susceptibility.

Amygdala↗
PubMedDate not supplied

[The sheath of Scarpa ganglion cells in the baboon Papio papio].

The sheath of the bipolar perikarya of the vestibular ganglion (Scarpa) in Papio papio is made up of several Schwann cells which concur to form loose myelin, and at most five layers of compact myelin. Most of the Schwann cytoplasmic layers stop at the emergence of both neurites, forming at the point an incomplete Ranvier half-node. The constitution of the vestibular perikaryal sheath in Papio is intermediate between those previously described in the Rat and in the Human.

Animals↗
PubMed1976

Measurement of anticonvulsant activity in the Papio papio model of epilepsy.

The status of Papio papio as a model of clinical epilepsy has been reviewed. The anticonvulsant effects of single doses of various classic and experimental agents have been compared against seizures induced in the P. papio by intermittent light stimulation. Long-acting but not short-acting barbiturates have been shown fully to control seizures with minor sedative effects. Diphenylhydantoin (in chronic doses only) and trimethadione are often effective but not consistently so. Diazepam and clonazepam block seizures at very low doses both acutely and chronically. However, an initial dose well above threshold seems essential if anticonvulsant effects are to be maintained under chronic administration of these compounds. Carbamazepine and SC 13504 (1-benzhydryl-4(6 methyl-2-pyridylmethyleneimino)piperazine), as well as two nonstimulant analogues of amphetamine, were shown to be promising anticonvulsants in this model. A biphasic action of tetrahydrocannabinol, anticonvulsant at a few micrograms per kilogram but not at higher doses, was also demonstrated. Finally, the anticonvulsant action of intraventricular epinephrine and norepinephrine was reported.

Animals↗
PubMed1985

Distribution of central cholinergic neurons in the baboon (Papio papio). I. General morphology.

The morphological characteristics of cholinergic neurons in the central nervous system (CNS) of the baboon (Papio papio) were studied by choline acetyltransferase (ChAT) immunohistochemistry and acetylcholinesterase (AChE) pharmacohistochemistry. The distributions of central cholinergic neurons as visualized by these two histochemical techniques were similar in most, but not all regions of the brain and spinal cord. Based upon these observations, central cholinergic neurons that are immunoreactive to ChAT and intensely stained for AChE by the pharmacohistochemical procedure can be divided into four major groups: (1) those in the caudate nucleus, putamen, nucleus accumbens and anterior perforated substance. These ChAT-containing and AChE-intense neurons are large and multipolar, and are scattered throughout these structures. (2) The rostral cholinergic column, which consists of a continuous mass of cholinergic perikarya situated in the medial septal nucleus, nucleus of the diagonal band, and nucleus basalis (Meynert). The ChAT-immunoreactive and AChE-intense cell bodies of the nucleus basalis are a prominent feature in the basal forebrain of the baboon. The labeled neurons are large, multipolar, and hyperchromic and show a tendency to aggregate in cell clusters. These cells are distributed within the full extent of the substantia innominata, often being associated with subcortical fiber networks such as the medullary laminae of the globus pallidus. (3) The caudal cholinergic column, which consists of a continuous group of cholinergic neurons in the caudal midbrain and pontine tegmentum. The rostral component of this group of cells is the nucleus tegmenti pedunculopontinus (subnucleus compacta) and it extends caudally to include the laterodorsal tegmental nucleus. Compared to that in other species the nucleus tegmenti pedunculopontinus in the baboon appears to occupy a relatively greater volume and is composed of a greater number of cholinergic neurons. The cells of the caudal column are large and hyperchromic. (4) Nuclei of origin of somatic and visceral efferents of the cranial nerves (III, IV, V, VI, VII, IX, X, XI, XII) and spinal nerves. In addition to these major cholinergic cell groups, a small population of ChAT-positive and AChE-intense cell bodies can be observed at the floor of the fourth ventricle and in lamina VII and X of the cervical cord. The present findings indicate that although some differences exist, the overall distribution and morphological features of cholinergic cell bodies identified in the baboon brain and spinal cord are similar to those demonstrated previously in investigations of the rhesus monkey and nonprimates.

Acetylcholinesterase↗