Increase In General Activity Research Articles

Electrostatics of cell membrane recognition: structure and activity of neutral and cationic rigid push-pull rods in isoelectric, anionic, and polarized lipid bilayer membranes.

Design, synthesis, and structural and functional studies of rigid-rod ionophores of different axial electrostatic asymmetry are reported. The employed design strategy emphasized presence of (a) a rigid scaffold to minimize the conformational complexity, (b) a unimolecular ion-conducting pathway to minimize the suprastructural complexity and monitor the function, (c) an extended fluorophore to monitor structure, (d) variable axial rod dipole, and (e) variable terminal charges to create axial asymmetry. Studies in isoelectric, anionic, and polarized bilayer membranes confirmed a general increase in activity of uncharged rigid push-pull rods in polarized bilayers. The similarly increased activity of cationic rigid push-pull rods with an electrostatic asymmetry comparable to that of alpha-helical bee toxin melittin (positive charge near negative axial dipole terminus) is shown by fluorescence-depth quenching experiments to originate from the stabilization of transmembrane rod orientation by the membrane potential. The reduced activity of rigid push-pull rods having an electrostatic asymmetry comparable to that in alpha-helical natural antibiotics (a positive charge near the positive axial dipole terminus) is shown by structural studies to originate from rod "ejection" by membrane potentials comparable to that found in mammalian plasma membranes. This structural evidence for cell membrane recognition by asymmetric rods is unprecedented and of possible practical importance with regard to antibiotic resistance.

Behavioral Demands on a New Exhibit for Greater Flamingos at the Basle Zoo, Switzerland

When the group of Greater Flamingos (Phoenicopterus ruber roseus) in the Basle Zoo, Switzerland, was moved to another area, the opportunity was taken to develop a new exhibit that reflected the behavioral demands of the flamingos to a greater extent than was possible at the old enclosure. The main objectives of at the new location were im- provement of the feeding situation and a reduction of the high egg losses in the breeding colony, which were interpreted as a husbandry problem. Because of the different structures in the new exhibit, the following goals were largely achieved: (1) a more natural behavior over the year; and (2) a general increase in activity, particularly foraging behavior and social stimulation. The start of breeding also become calmer, and egg losses in the settling colony were reduced.

The effects of changing straw provision on the feeding behaviour and activity of growing pigs given food through single-space feeders

AbstractIn a previous experiment the provision of straw to group-housed pigs increased the number of daily feeder visits. This effect of straw is comparable with conditions of reduced social competition for access to the feeder. The aim of this experiment was to investigate if changing straw provision within a pen resulted in similar and reversible effects in this behaviour. One hundred and twenty male pigs (41·1 (s.e. 0·43) kg) were used in three blocks each of four pens of 10 pigs. In each block of 42 days duration one pen had no straw throughout (treatment 1); one pen had no straw for 21 days (period 1) followed by straw for 21 days (period 2) (2); one pen had straw followed by no straw (3) and one pen had straw throughout (4). The pens were situated in a naturally ventilated building with light from 06.00 to 20.00 h. Each pen had a kennel, a lying area and a single-space computerized feeder for recording feeding behaviour. The pigs’ activity was recorded on video in the 2nd and 5th weeks of each block. The number of feeder visits was slightly higher for pigs with straw (1: 9·69 v. 4: 10·46) but this was not significant (P > 0·05). The effect was more marked for treatment 2 where the visits increased (P < 0·01) from period 1 (8·52) to period 2 (10·64) and for treatment 3 where they decreased (11·20 v. 10·10). Pigs without straw (treatment 1) spent more time in the kennel than those with straw (treatment 4) (P < 0·05). For treatment 2 the proportion of time spent in the kennel fell from 0·607 in period 1 to 0·288 in period 2 (P < 0·01). There was a general trend for more activity and more lying outside the kennel when straw was provided. The effect of straw provision was not as marked as that seen previously; nevertheless changing straw provision (treatments 2 and 3) did result in an increase in feeder visits with straw, probably related to the increase in general activity and lying outside in the area adjacent to the feeder.

Age and Behavior of Honey Bees, Apis mellifera (Hymenoptera: Apidae), that Perform Vibration Signals on Workers

AbstractThe vibration signal is one of the most commonly occurring communication displays in honey bee (Apis mellifera) colonies. It may function in a ‘modulatory’ manner, because it causes a nonspecific increase in activity that enhances a variety of behaviors depending upon the age and caste of the recipient. We examined honey bee workers that performed vibration signals on other workers in three observation hives, each containing a population of marked bees of known age. In all three colonies, the mean age of the first performance of the vibration signal was significantly different from the mean age at which workers first performed waggle dances, carried pollen loads, or attended the queen. However, workers of all ages, except those less than 3 d old, could perform vibration signals. In older workers of foraging age, signal performance was most closely associated with recent foraging success. Younger workers that vibrated did not appear to be early‐maturing foragers and thus their signals were probably not influenced by food collection. Rather, for these preforaging‐age workers, signal performance was associated more with periods of orientation flight, during which younger bees learn the location of the nest and surrounding landmarks. Thus, the vibration signal may be triggered by different stimuli in different worker age classes. Because it elicits a general increase in activity in all recipients, the signal may help adjust many different colony behaviors simultancously to changes in foraging success and colony development.

Effects of localized injections of neuropeptide Y antibody on motor activity and other behaviors

Neuropeptide Y (NPY) was shown to increase feeding when injected into the hypothalamus. Neuropeptide Y antibody (aNPY) decreased feeding in the ventromedial area of the hypothalamus as well as when it was injected into the ventromedial or ventrolateral areas of the thalamus, but not when injected into other hypothalamic areas. The decrease in feeding produced by aNPY in the hypothalamus was associated with a sterotypic increase in general activity in the hypothalamus, circling in the ventromedial thalamic area, and barrel rolling in the ventrolateral thalamic area. Neuropeptide Y antibody also reduced by 54–73% the time it required for mice to recover from anesthesia. The marked increase in stereotypic activity and enhanced recovery from anethestic suggest that blocking endogenous NPY released the brain areas from inhibitory control. These studies further confirm a physiological role for NPY in the central nervous system.

Potential Antidepressive Properties of Amantadine, Memantine and Bifemelane

The effects of amantadine, its dimethyl derivative, memantine and the chemically unrelated compound bifemelane were tested for antidepressant activity. Reserpine-induced hypothermia and the forced swim test (Porsolt test) were selected for this purpose. In the former test amantadine and bifemelane but not memantine were effective. In the forced swim test all three agents produced antidepressive-like activity (decreased immobility time), but in case of bifemelane it was less pronounced. The effect in the forced swim test was specific i.e. it was apparently not the result of an increase in general activity as evidenced by control experiments in the open field. The mechanism of amantadine and memantine action may involve indirect dopaminomimetic activity resulting from the blockade of NMDA receptors. However in reserpine-induced hypothermia this explanation is not valid considering the lack of effect of memantine and positive action of amantadine. Hence, amantadine may have an additional central sympathomimetic action that memantine is lacking. Bifemelane antidepressant-like activity might be attributed to an enhancement of noradrenergic transmission. We suggested that amantadine and bifemelane could be particularly useful therapeutically when depressive symptoms are present in patients suffering from Parkinson's disease and dementia.

Cholinergic transmission at the first synapse of the circuit mediating the crayfish lateral giant escape reaction.

1. The chemical synapses between mechanoreceptor neurons and first-order interneurons in the lateral giant (LG) neuron escape circuit of the crayfish have plastic properties, some of which are believed to be the basis for behavioral habituation and sensitization. In this investigation pharmacological experiments were conducted to assess the role of cholinergic synaptic transmission in this pathway. 2. Arterial perfusion of the cholinergic agonist carbachol produced increased activity of many abdominal nerve cord units, including an identified first-order interneuron (interneuron A) in the LG circuit. A general increase in activity of interneurons in this circuit in the presence of certain cholinergic agonists was inferred from an increase in the frequency of occurrence of spontaneous excitatory postsynaptic potentials (EPSPs) recorded in the LG. 3. Cholinergic antagonists reduced the amplitude of spontaneous and evoked sensory neuron-to-interneuron A EPSPs and decreased the disynaptic (via 1st-order interneurons) component of evoked EPSPs in the LG. These effects indicate that postsynaptic cholinergic receptors are utilized in mechanosensory synaptic transmission to the first-order interneurons of this circuit. The relative potencies of the blockers tested (mecamylamine > picrotoxin >>> curare > atropine) suggest that the receptors on the interneurons belong to a previously characterized class of crustacean cholinergic receptors that resemble the ganglionic nicotinic subtype of vertebrates. 4. Nicotinic agonists (carbachol, tetramethylammonium hydroxide, 1,1-dimethyl-4-phenyl-piperazium iodide) produced depolarizing (decreased input resistance) responses on the LG neuron itself. These responses persisted during blockade of chemical transmission by cobalt. The presence of cholinergic receptors on the LG, a cell in which all known inputs mediating sensory excitation are electrical, is discussed. 5. Application of muscarinic agonists (pilocarpine, oxotremorine) resulted in a long-lasting reduction of the evoked sensory neuron-to-interneuron A EPSP and the disynaptic component of the evoked EPSP in the LG. No effects on the membrane potential or input resistance of the interneurons were detected. It is proposed that presynaptic receptors with a muscarinic profile are present on mechanosensory neurons and that these receptors mediate a reduction of transmitter release.

Variations in time budget of the polychaete Nereis virens as a function of density and acclimation after introduction to a new burrow

Behavioural patterns of Nereis virens (Sars) were monitored in the laboratory to determine variations in the time budget (i.e., percentage of time spent in various activities) as a function of density and acclimation period (number of days following the introduction of worms into experimental enclosures). Experiments were carried out from 17 June to 13 August 1989, using worms collected from intertidal sand flats of l'Anse a l'Orignal in the lower Saint Lawrence estuary, Canada. Inactivity, locomotion and irrigation were, in that order, the most frequent behaviours for solitary individuals. Correlations between the time spent in the various activities and time of day indicated a general increase in activity during the night (21.00 to 06.00 hrs). Locomotory activity increased at night, inactivity during the daytime. A general sequence of behaviour of N. virens was revealed. Inactivity, locomotion and irrigation were still the most frequent activities for individuals observed in high-density conditions, but their respective importance differed significantly (locomotion, irrigation and inactivity, in that order). There was also less variability in the time spent for each behaviour in the high-density aquarium. Comparisons between behaviour and time of day suggested fewer correlations among the different components of the time budgets under conditions of high density. Finally, the time budget varied but little over time (number of days alloved for acclimation) in the low-density aquarium as opposed to the high-density aquarium. Our study revealed that population density and acclimation are important in determining behavioural patterns of N. virens.

Excitotoxic lesions of the septum produce anxiolytic effects in the elevated plus-maze and the shock-probe burying tests

Our previous research has shown that electrolytic lesions of the posterior septum result in dramatic, antianxiety effects in two different animal models of anxiolytic drug action, i.e., a selective increase in open-arm activity in the elevated plus-maze test, and a selective abolition of defensive burying in the shock-probe burying test. Although these results suggest that posterior regions of the septum play an important role in the expression of anxiety in these tests, it is unclear whether destruction of septal nuclei themselves mediated these effects, since electrolytic lesions also destroy fibers of passage. Accordingly, in the present experiments, the anxiolytic effects of electrolytic lesions of the septum were compared to those of excitotoxic lesions, which preferentially destroy cell bodies, leaving fibers of passage intact. In the first experiment, both electrolytic and kainic acid lesions of the posterior septum produced complete anxiolytic effects in the elevated plus-maze (an increase in the percentage of open-arm entries and percentage of time in open arms), and partial anxiolytic effects in the shock-probe test (an increase in contact-induced probe shocks), compared to sham-lesioned controls. These antianxiety effects could not be attributed to an increase in general activity, or a decrease in reactivity to shock. In the second experiment, excitotoxic lesions of the posterior septum were produced by a more selective agent, quisqualic acid. Quisqualic acid, like electrolytic lesions, produced clear, anxiolytic effects in both the plus-maze and the shock-probe tests, compared to sham-lesioned control. Taken together, these results strongly suggest that cells originating in posterior regions of the septum mediate anxiety-related responses.

The effects of odors from stressed mice on conspecific behavior

Four experiments correlate conspecific reactions to odors from stressed (foot shocked) BALB/cJ mice with the frequency of specific motor activities and taste avoidance. Where behavior was restricted to forward and backward movement in a tube, animals tended to avoid the side where the odors from stressed animals entered. In a more socially complex home cage (3 recipients) a wide variety of behaviors were affected by odors from stressed conspecifics. Animals were alerted by the odor, searched out the source of the odor and showed increases in general activity, rearing, and air sampling. Many of these behaviors habituated with continuous exposure. The major response to odors from stressed animals was to increase “vigilance.” A restriction of behavioral opportunities will lead to odor avoidance; however, when the environment permits, the behavioral reaction to odors becomes more complex. These odors failed to produce conditioned taste aversion, suggesting a sensory specificity in the use of these odors.

Behavior of monkeys during opiate withdrawal and locus coeruleus stimulation.

The noradrenergic nucleus locus coeruleus (LC) has been implicated in morphine withdrawal. The behavioral effects of opiate antagonist-precipitated morphine withdrawal in chair-restrained Macaca arctoides were therefore compared with LC electrical field stimulation. Both continuous LC stimulation and administration of low doses of naloxone to morphine pellet implanted monkeys produced a significant increase in the same group of behaviors reported previously to follow activation of the LC, without significant increases in general activity or distress behaviors. Signs of autonomic hyperactivity and distress were observed at high doses of naloxone, but not during LC stimulation. Monkeys which had not received morphine treatment did not specifically increased during low intensity LC stimulation is also selectively increased during naloxone-precipitated morphine withdrawal. These data are consistent with and suggest a behavioral consequence of the interactions of opioids with the LC reported at the molecular, intracellular, and cellular level.

Interpretation of fusimotor activity in cat masseter nerve during reflex jaw movements.

Simultaneous recordings were made from fusimotor axons in the central ends of filaments of the masseter nerve, and from masseter and temporalis spindle afferents in the mesencephalic nucleus of the fifth cranial nerve in lightly anaesthetized cats. Fusimotor and alpha-motor units in the masseter nerve were differentiated on the basis of their response to passive ramp and hold stretches applied to the jaw. Spindle afferents were identified as primary or secondary according to their dynamic index after administration of suxamethonium. The activity of a given fusimotor unit during reflex movements of the jaw followed one of two distinct patterns: so-called 'tonic' units showed a general increase in activity during a movement, without detailed relation to lengthening or shortening, while 'modulated' units displayed a striking modulation of their activity with shortening, and were usually silent during subsequent lengthening. Comparison of the simultaneously recorded fusimotor and spindle afferent activity suggests that modulated units may be representative of a population of static fusimotor neurones, and tonic units of a population of dynamic fusimotor neurones. In these lightly anaesthetized animals, both primary and secondary spindle afferents showed increased firing during muscle shortening as well as during lengthening. This increase during shortening is not usually seen in conscious animals and reasons are given for the view that it is due to greater depression of alpha-motor activity than of static fusimotor activity during anaesthesia. The results are discussed in relation to the theories of 'alpha-gamma co-activation' and of 'servo-assistance'; and it is suggested that static fusimotor neurones provide a 'temporal template' of the intended movement, while dynamic fusimotor neurones set the required dynamic sensitivity to deviations from the intended movement pattern.

Motivational properties of ethanol in naive rats as studied by place conditioning

The reinforcing properties of ethanol were examined in naive adult male rats by means of a place conditioning paradigm that has previously demonstrated the positive reinforcing properties of food, water and some drugs, and the aversive properties of punishers such as electric shock and lithium chloride. Only doses of 0.8–1.0 g/kg and higher produced clear place conditioning, and this was only conditioned place aversion; rats spent significantly more time on the side of the place conditioning box in which they received the vehicle than on the side in which they received ethanol. Doses between 0.1 g/kg and 0.8 g/kg produced increases in general activity, but did not produce any place conditioning. Control experiments indicated that the pattern of effects was not specific to the route of ethanol administration (intravenous or intragastric), rate of infusion, concentration, or vehicle. It was concluded that ethanol, in the doses used here, has only punishing or neutral motivational effects in naive rats and does not serve as a primary positive reinforcer in this model. The conclusions are discussed in relation to the relative difficulty encountered in attempts to produce ethanol self-administration, and the findings are viewed as consistent with a proposal that prolonged training and experience with ethanol are important for ethanol self-administration by the rat.

Some naturally occurring mild stressors in dairy herds and their consequences

Two projects were designed to examine the effects of three potentially stressful variables in dairy cows. The naturally occurring state of oestrus involves a considerable increase in general activity and in the frequency of agonistic interactions, as well as in overt sexual activity. It is also frequently associated with a reduction in milk yield, and it is known that milk ejection can be inhibited by a variety of disruptive environmental stimuli. Data were collected from a 73cow dairy herd during its breeding season in an attempt to determine whether the reduction in milk yield during oestrus can be attributed to a state of behavioural stress. No significant relationship was found between the degree of involvement of individual cows in oestrous behaviour and the suppression of their yield. Nor did the somatic cell count in milk, widely regarded as one physiological indicator of stress, increase during oestrus. In the second project, the effects of short-term water deprivation and manipulation of parlour entry-habits were examined. The herd was normally subdivided on entry to the parlour collecting yard, with individuals regularly designated for a particular side of the parlour. For the duration of the project, this subdivision was also maintained during grazing. During the course of 5 observation days, one sub-herd was water-deprived for 6 h between morning and afternoon milking on the second day, and the other sub-herd was similarly treated on the fourth. In addition, on the same days, 6 cows were exchanged between the two sides of the parlour at the afternoon milking. Water deprivation resulted in a disruption of the normal cycles of grazing and lying, and in an increase in loafing and agonistic behaviour near the trough. There was also a 6% reduction in milk yield at the afternoon milking. Milking on the non-habitual side of the parlour resulted in a similar reduction in milk yield at the afternoon milking and a rise in somatic cell count in milk on the following morning. THE OPEN FIELD AS A STRESSOR: FEAR IN DOMESTIC CHICKS R.B. JONES ARC Poultry Research Centre, Roslin, Midlothian (Gt. Britain)

Structure analysis of spontaneous behavior during the estrous cycle of the rat

The structure of spontaneous motor behavior during estrous and diestrous stages of the adult female rat's reproductive cycle was analyzed using time-lapse photography. Repeated measures of the frequency, duration, sequences and distribution of fifteen different motor acts were taken for each female in diestrus and again during estrus. In contrast to findings of previous studies, no increase in general activity was observed in correlation with the physiological condition of estrus. Furthermore, consideration of factors including the individual, environment and estrous cycle stage demonstrated that the individual was most important, the environment next and estrous cycle stage least for influencing behavior sequence consistency. Consequently, these results, from a more complete, quantitative analysis of female spontaneous behavior, do not support the widely accepted belief that female rats' motor activity varies with estrus to preclude their use in studies of behavioral toxicity.

Electrocatalytic Activity of Cubic Sodium Tungsten Bronze: I. Effects of Platinum Doping, Anodization, and Platinum Pre‐Electrolysis of the Electrolyte

The electrocatalytic activity of cubic sodium, tungsten bronzes, including high purity and platinum‐doped crystals, has been measured for oxygen reduction before and after anodization in both fresh and platinum pre‐electrolyzed acid solutions. The effects of platinum doping, anodization, and platinum pre‐electrolysis have been separately studied for current densities between 10−8 and 10−3 A/cm2. A previously unreported break in the Tafel curve at was observed for all clean undoped bronze samples. Below this break the Tafel slope was −110 mV/decade while above it the Tafel slope was −200 mV/decade. Anodization of a pure bronze electrode failed to produce any change in the Tafel curve. Platinum pre‐electrolysis of an anodized, undoped bronze produced a general increase in activity for all current densities. The break in the Tafel curve increased to while the Tafel slopes above and below this current density were unchanged. Platinum doping to 130 ppm increased the electrode activity at current densities below, even when measured in platinum‐free solutions before anodization of the electrode. The increased activity of an unanodized electrode in fresh solutions could be accounted for by the surface platinum concentration expected from the bulk platinum doping. Anodization of a doped bronze electrode increased the limiting current from even in fresh solutions while subsequent platinum pre‐electrolysis increased the limiting current to . Auger analysis of the anodized, platinum‐doped electrode exposed to the platinum pre‐electrolyzed solution revealed platinum on the surface of the bronze electrode at a coverage sufficient to account for the increased electrode activity below . A small but reproducible increase in activity was found at high current densities near 10−3 A/cm2 after either a pure or platinum‐doped bronze electrode was exposed to a platinum pre‐electrolyzed solution that lead to the research reported in the following paper (II).

The interaction of a fixed time food delivery schedule and body weight on self-administration of narcotic analgesics

Experiment 1 reported the effects of the interaction of a fixed 1 min delivery schedule and body weight, using schedule-induced self-injection paradigm, in the rate of acquisition of methadone and heroin. Eighty-one rats were assigned to 100% and 80% reduced body weight conditions with and without a schedule. The findings show that: (a) voluntary heroin and methadone intake was enhanced when a schedule was introduced to animals at 80% but not at 100% body weight; (b) high intake of heroin and methadone was accompanied by increased levels of plasma 11-OHCS. Experiment 2 showed that the high rate of self-injection was due to the interaction of pharmacological properties of opiates and environmental variables rather than to a general increase in activity arising from the deprivation state or the effects of the schedule. The results are discussed in terms of a stress factor arising from an interaction between environmental and pharmacological factors.

Effects of 6-hydroxydopamine and 6-hydroxydopa on development of behavior

Rats treated at birth with 6-hydroxydopamine (6-OHDA) (60 μg/g, IP) or 6-hydroxydopa (6-OHDOPA X2) (60 μg/g, IP at birth and 48 hr later) exhibited increases in general activity throughout the initial 5 weeks after birth, with peak activity occurring around 20 days postnatally. Activity changes in the 6-OHDOPA×2 group appeared to be due to increased exploratory behavior (ambulation, climbing, rearing, sniffing), while the 6-OHDA changes appeared to be due to the increased self-directed behavior (eating, grooming, scratching). Despite these behavioral differences there was no obvious difference between treated groups in norepinephrine (NE) levels in the various brain regions, i.e., all treatments resulted in a reduction in neocortical and hippocampal NE and an elevation in cerebellar NE. These findings suggest that noradrenergic neurons may be altered to different degrees by each agent in more discrete brain regions than tested, or that other neurotransmitter systems may be more selectively altered by either of the drug treatments. Because striatal dopamine was unaltered in any of the groups, however, there is a reason to question a previously suggested link between minimal brain dysfunction (MBD) and dopamine depletion in the neonatal brain.

Behavioral evaluation of sensory irritation evoked by ammonia

Mice will respond to escape from ammonia vapor, a prototypical airborne chemical irritant. Nose poking at a conical sensor is maintained if it terminates the delivery of ammonia to a small exposure chamber and produces a facial shower of clean, humidified air from the sensor. The duration of exposure to ammonia tolerated decreased as ammonia concentration increased (0.0–0.2%). The percentage of ammonia deliveries terminated by a response also increased as concentration increased. The behavior did not result from a general increase in activity. Thus, ammonia vapor delivery is an effective negative reinforcer for the mouse. This technique can help evaluate the aversive properties of atmospheric contaminants.

Leaf Formation and Peroxidases from Arabidopsis Callus

Summary A progressive decline of leaf formation capacity was observed in long-term cultures of Arabidopsis callus on 2,4-D. It corresponded to a gradual loss of activity of total peroxidase and of specific isoperoxidases. A passage on media without auxin was required to restore the morphogenetic capacity. It was accompanied by a general increase of activity for most of the isoperoxidases. Leaf formation by passing on a third medium with low IAA level and high kinetin content paralleled a continuous increased enzyme activity as mentioned before by different authors on other materials. The results suggested that morphogenetic potential is dependent upon an endogenous hormonal balance controlled by the exogenous regulators.