Voluntary alcohol consumption in vervet monkeys: individual, sex, and age differences.

The patterns of voluntary alcohol consumption were studied in 35 vervet monkeys (Cercopithecus aethiops), classified into four groups. Each monkey showed a fairly steady rate during the studied period, resulting in individual differences that became more evident as the treatment evolved. Females showed higher alcohol intake frequencies than males. This sexual difference was maintained among adults and juveniles. Age differences were also observed: juveniles showed higher frequencies of intake than adults, both in general and in each sex group. Intake frequency was not related to age in prepubertal subjects, neither in general nor in each particular sex. The origin of these sex and age alcohol consumption differences remains to be studied, but differences in alcohol metabolism and factors related to puberty are possible influences.

Voluntary consumption of beverage alcohol by vervet monkeys: population screening, descriptive behavior and biochemical measures.

Seventeen percent of 196 feral vervet monkeys (Cercopithecus aethiops) spontaneously drank appreciable quantities of beverage alcohol in 3% sucrose in preference to 3% sucrose alone. Ethanol consumption increased over time, as did the concentration of ethanol tolerated. Willingness to select ethanol was stable over a three-year period, as measured by periodic retesting. Individual patterns of drinking and behavioral responses to ethanol were quite variable. Upon occasion, some animals drank to ataxia and unconsciousness; signs of withdrawal, including tremulousness, pacing, irritability and increased aggression, followed the abrupt discontinuation of ethanol availability. A variety of changes in social interaction, including increased orientation to external stimulus, increased incidence of stereotyped aggression and of other stereotyped behaviors and decreased frequency of affiliative behaviors were observed during ethanol periods, as compared to baseline scoring periods. In a small number of alcohol-preferring animals, CSF amine metabolites (5-hydroxyindoleacetic acid and homovanillic acid) were raised by drinking alcohol. These studies suggest that the alcohol-selecting vervet monkey may be complementary to established primate models of alcoholism.

Modifications of acoustic habituation by interruption of visual input in quipazine treated cats.

The influence of interruption of the visual input on acoustic habituation was studied in cats before and following the administration of quipazine, 3 mg/kg iv. The characteristics of acoustic habituation were analyzed through the magnitude and temporal course of multiunit activity (MUA) responses elicited in the mesencephalic reticular formation (MRF) by repetitive acoustic stimuli (70 db, 50 Hz trains of 2 sec duration) in 6 freely moving cats with cortical electrodes over the parietal cortex and bipolar electrodes chronically implanted in MRF and basolateral amygdala (AMN). The cats were submitted to repetitive acoustic stimulation during one 30 min period before, and three 30 min periods after drug administration in the following conditions: a) with unmasked eyes; b) with masked eyes by means of dark contact lenses. Persistent attentive behavior, catatonic attitudes, hypersynchronous (6 Hz, 100-150 microV) EEG activity and significant increase of spontaneous MUA in FRM and AMN were induced by quipazine both in the cats tested with unmasked and with masked eyes. This increase of MUA was higher immediately following drug administration and progressively decreased, although MUA values remained significantly higher than controls 110 min after quipazine administration. Acoustic habituation, evidenced through the progressive decrease of MUA responses of MRF to acoustic stimuli, was observed before quipazine administration when the cats were tested with unmasked and with masked eyes; as well as in cats tested with unmasked eyes following drug administration. However, the MUA responses to acoustic stimuli did not decrease in cats with masked eyes during acoustic stimulation periods 0-30 min and 40-70 min after quipazine administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in social dynamics associated to the menstrual cycle in the vervet monkey (Cercopithecus aethiops).

Behavioral changes associated to the menstrual cycle in a social group of vervet monkeys (Cercopithecus aethiops) were studied. Three adult females were used as experimental subjects and in these, vaginal smears were taken every other day in order to detect their menstrual cycles. Only the dominant and the mid-ranking female showed regular cycles while the low-ranking female showed amenorrhea. The menstrual cycles were divided into five periods (menstrual, premenstrual, luteal, ovulatory and follicular) which were related to the behavioral data. Social behavior recordings were taken during one hour daily for five consecutive months; the data were adjusted twice in order to follow the cycles of the females with regular menstruations. By plotting in a matrix the relative frequencies of joins and displacements, the social position of each animal as well as the group's social organization and dynamics were evaluated. A clear tendency towards social rejection (emitting less joins and increasing the amount of displacements) was detected during the premenstrual periods of the dominant female which abruptly changed towards affiliation during menstruation. This observation was detected in all group members no matter their age-sex class or social position during the five months of observation. When the data were analyzed following the mid-ranking female's cycle, no consistent changes were apparent. The importance of social stimuli in the modulation and expression of hormone-related behavior is stressed, as well as the need of using social settings in the experimental analyses of premenstrual mood and behavior disorders.

Lateralization of spike and wave complexes produced by hallucinogenic compounds in the cat.

The ability of four hallucinogenic compounds--ketamine, phencyclidine, quipazine, and SKF-10 047--to produce some specific electrical pattern in portions of the limbic system and the hemispheric lateralization of such effects were studied in cats with permanently implanted electrodes. Electronic frequency and area integrators were used to analyze the results, and the percentage change in electrographic alterations was calculated. All compounds studied produced trains of spike and wave complexes in the cingulum, rapid discharges in the amygdala complex, and slow-wave synchronous activity in the septal nucleus. Those changes predominated in the left hemisphere. At small but hallucinatory concentrations of these drugs, the cortical EEG was not affected. Exploratory movements directed toward nonexistent objects, classified as hallucinatory-like behavior, appeared simultaneous with these changes in the EEG recordings. We concluded that there could exist a relationship between the appearance of spike and wave complexes in the limbic system without epileptic signs (twitching or myoclonus) and the presence of hallucinations, and that there is a left side hemispheric lateralization of the electrographic effects, viewing cerebral dominance phenomena as a functional and fluctuating state.

Spike and wave complexes produced by four hallucinogenic compounds in the cat.

The ability of four hallucinogenic compounds: ketamine, phencyclidine, quipazine and SKF-10,047 to produce spike and wave activity in the limbic system, was studied in cats with permanently implanted electrodes. Electronic frequency integrators were used to analyze the results and the percent of change in electrographic alterations was calculated. All the compounds studied, produced trains of 6/sec spike and waves complexes in the cingulum, rapid synchronous discharges in the amygdaloid complex, and slow wave synchronous activity and spiking in the septal areas. At low but hallucinatory concentrations of these drugs, the cortical EEG was not affected. Exploratory movements directed toward non-existent objects, classified as hallucinatory-like behavior, appeared simultaneous with these changes in the EEG recordings. It was concluded that there could exist a relationship between the appearance of 6/sec spike and wave complexes in the cingulum and the presence of hallucinations, produced by some synthetic drugs in the cat, this activity could be interpreted as the spreading of altered function of limbic and non-limbic nuclei related with this bundle which explain unspecificity of action.