Changes In General Activity Research Articles

Deficits in Reproductive Behavior in Diabetic Female Rats Are Due to Hypoinsulinemia Rather Than Hyperglycemia

These studies determined whether deficits in reproductive behavior observed in streptozotocin (STZ)-induced diabetic female rats are caused by hyperglycemia or loss of insulin. Female Sprague–Dawley rats were ovariectomized and made diabetic by a single ip injection of STZ (75 mg/kg). Reproductive behavior was measured 12 days after the onset of hyperglycemia following the injection of estrogen and progesterone in doses known to restore reproductive behavior in nondiabetic rats. Rats in which STZ produced diabetes showed significantly reduced receptive and proceptive sexual behaviors. Normalization of blood glucose levels either by restricting diet or by phlorizin treatment failed to restore reproductive behavior in diabetic animals. However, even doses of insulin which were not fully effective in correcting peripheral hyperglycemia were able to prevent the STZ-induced behavioral deficit. No changes in general activity were observed in any experimental group as assessed by open field activity. The density of the norepinephrine transporter, as measured by [3H]nisoxetine binding, was reduced in the cortex but not in the brain stem, hypothalamus, or hippocampus of diabetic animals. Insulin treatment prevented the loss of cortical [3H]nisoxetine binding, and even partial normalization of blood glucose restored cortical [3H]nisoxetine binding to control levels. These findings suggest that diabetes-induced reproductive deficits are due to hypoinsulinemia and cannot be corrected simply by the normalization of blood glucose, whereas reductions in the density of cortical norepinephrine transporter result from hyperglycemia.

General activity in baboons measured with a computerized, lightweight piezoelectric motion sensor: Effects of drugs

A small, 1-oz activity-monitoring device is described for measuring motor activity continuously for periods of up to 42 days. The monitor employs a piezoelectric sensor that detects extremely small accelerations induced by movements. The monitor can be placed on collars or harnesses (e.g., for rabbits, cats, dogs, nonhuman primates, etc.). The use of the monitor is described within numerous laboratories studying the behavioral pharmacology of drugs in individually caged laboratory baboons. Patterns of daily activity were reliably recorded over periods of several months, and reflected the normal activity patterns of animals. The activity monitor recorded reliable drug-induced changes in general activity that paralleled the known effects of the same drugs on learned behaviors. Low doses of the stimulants cocaine and d-amphetamine both increaed general activity. Marked reductions in general activity were observed following both the administration of Δ-9-tetrahydrocannabinol and an antihypertensive drug combination of diuretic and verapamil.

Effect of Acute Cocaine Administration on the Cholinergic Enzyme Levels of Specific Brain Regions in the Rat

Adult male Sprague-Dawley rats weighing between 170 and 204 g and maintained under controlled lighting and temperature conditions were used in this experiment. One group of animals was treated with 30 mg/kg of cocaine hydrochloride and the other group with saline. Rats were decapitated 20 min after cocaine injection and their brains were removed and the different regions including the medulla, pons, midbrain, cerebellum, hypothalamus, thalamus, hippocampus, and the cortex were dissected. All brain regions were assayed for choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities. The results obtained indicated that the administration of cocaine was associated with significant increases (p less than 0.01) in AChE activity in the medulla, pons, midbrain, hypothalamus, thalamus, and also in the hippocampus (p less than 0.05). A significant decrease in ChAT activity was found in the pons (p less than 0.01), hypothalamus, and thalamus (p less than 0.05), while a significant increase in ChAT activity was found in the cortex (p less than 0.05). The results suggest that the changes in general activity followed by stereotypic behavior may be related to the changes in the levels of cholinergic enzymes in specific brain regions.

Chronic intrastriatal dopamine infusions in rats with unilateral lesions of the substantia nigra

This study examined the effects of continuously supplied dopamine delivered directly into the dopamine-deficient striatum. Rats received unilateral lesions of the substantia nigra by stereotaxic administration of 6-hydroxydopamine and were tested for apomorphine-induced rotational behavior and general activity. Osmotic mini-pumps were filled with dopamine in various concentrations, implanted subcutaneously and connected to a cannula implanted directly into the striatum. The system delivered solution at a rate of .5 μl/hr for two weeks. Dopamine in a dosage of 0.5 μg/per hour reduced apomorphine-induced rotational behavior by a mean of 52 ± 5.8% (mean ± SEM, n = 20) with a maximal individual decrease of 99%. There was no change in general activity or increase in stereotyped behavior. Infusions of vehicle solutions did not decrease rotational behavior. Spread of the infused dopamine and its metabolites was estimated by adding 3H-dopamine to the pumps in tracer quantities. Radioactivity was highly concentrated at the infusion site and decreased rapidly within a few mm from the infusion site. Continuous infusion methods may eventually prove to be effective in the treatment of nigro-striatal degenerative disease.

Aggressive behavior inhibition by serotonin and quipazine injected into the amygdala in the rat

The effects on aggressive behavior, open-field activity, and pain threshold of bilateral microinjections of serotonin (20 micrograms) and quipazine (20 micrograms), the direct serotonergic receptor agonist, into the cortico-medial amygdala were investigated in Wistar rats. Both drugs significantly prolonged the attack latency in isolated killer rats (predatory aggression model), and suppressed the incidence of aggressive postures/attacks in shock-induced fighting test (affective aggression). The only difference in the open-field behavior was the lower number of central square entries in drug-treated compared to saline-injected rats. None of the substances produced any significant change in jump threshold. It is concluded that stimulation of serotonin receptors within the amygdala produces inhibition of affective and muricidal behavior in isolated rats. The effect does not seem to be dependent on changes in general activity and pain sensitivity.

Defensive burying: Effects of diazepam and oxprenolol measured in extinction

When a rat is shocked via a prod in a chamber with sawdust on the floor it will typically push the flooring material with snout and forepaws towards and over the prod. We administered diazepam (.5 and 1.0 mg/kg) and oxprenolol (10 and 20 mg/kg) the day following shock exposure, and observed the complete suppression of burying by diazepam, and some suppression with oxprenolol. These effects are independent of interference with initial association of shock and prod, and of changes in general activity.

Vasopressin-induced antinociception: an investigation into its physiological and hormonal basis.

Systemically administered lysine-8-vasopressin (LVP; 16-128 micrograms/kg) was found to induce a potent and dose-dependent antinociceptive effect, as measured by the tail-flick test in the rat. This effect could be seen in the absence of any significant change in general activity, indicating that it was not due to sedation or general motor debilitation. The antinociceptive effect of LVP does not appear to be mediated by endogenous opiates or other pituitary hormones, as evidenced by: 1) the lack of antagonism by the opiate receptor blocker naloxone, 2) the lack of cross-tolerance with morphine, and 3) its persistence after hypophysectomy. Des-glycinamide-LVP, a vasopressin analog with no appreciable pressor or antidiuretic action, showed no antinociceptive activity (128 micrograms/kg), and des-amino-arginine-vasopressin, a vasopressin analog with minimal pressor activity but greatly enhanced antidiuretic activity, was also relatively ineffective (128 micrograms/kg). These results suggest that the antinociceptive activity of vasopressin may be related to receptor types similar to those mediating its pressor effects. Nevertheless, the antinociceptive action of vasopressin does not appear to be secondary to its pressor activity, since phenylephrine failed to induce an antinociceptive effect at a dosage that mimicked the pressor response to vasopressin. These results are in concert with a growing body of evidence suggesting that vasopressin may be one of several nonopiate peptides that play a role in the modulation of pain sensitivity.

Superior colliculus involvement in the locomotor effects of ambient noise and the stimulants

Partial destruction of the superior colliculus (45%) significantly decreased the normal facilitatory effect of ambient white noise on locomotor activity levels in young rats. As recovery from surgery occurred and as test experience increased, the loss observed immediately following surgery was reduced. Presumably because of the age of the rats examined, destruction of the superior colliculus failed to potentiate the stimulant effects of d-amphetamine or methylphenidate on locomotion. These data suggest that the superior colliculus is involved in changes in general activity that result from manipulation of auditory stimuli in the environment in addition to the documented involvement of the superior colliculus in alterations of general responsivity resulting from manipulations of visual stimuli in the environment. Moreover, the superior colliculus is implicated in maintaining both excitatory and inhibitory changes in response to the environment of the organism.

Circadian patterning of feeding, drinking and activity during diurnal food access in rats

Using an “ecologically” relevant approach, the present study investigated (1) the association between feeding and drinking patterns and their circadian organization and (2) changes in general activity (or life-style), during ad lib conditions (fa:LD) and in a situation where access to food was restricted to the light phase (fa:L). Rats were housed in large outcages with nest boxes. Feeding, drinking, activity, outcage and nest occupation were recorded automatically throughout the day-night cycle. Access to food was restricted by a sliding door situated in front of the food hopper. Under ad lib conditions rats were mainly nocturnal, eating 94% and drinking 95% of their daily intakes at night. The patterns of food and water intake were similar, showing a bimodal distribution over the dark phase. During fa:L rats showed an initial large peak in feeding with lights on, followed by a long pause. Thereafter, feeding activity was variable but remained at a low level. The nocturnal drinking pattern persisted. However, 17.5% of daily water intake was meal-associated, compared with 71% during ad lib. Diurnal activity was associated with feeding and nocturnal activity with drinking. Nocturnal outcage and nest occupation patterns were not shifted to the light phase. The experiment demonstrates that rats on an fa:L schedule reduce food and water intake, and body weight, while still retaining circadian characteristics in the temporal distribution of drinking, activity, outcage and nest occupation. Further, although feeding and drinking may be causally related they need not occur in close temporal association. The rapidity of re-establishment of the normal feeding pattern, on return to free-feeding, and the close association with drinking under normal conditions, suggest the existence of a single or two coupled oscillators controlling feeding and drinking.

Correlation between estrus and reduced light avoidance in mice

Female CD-1 mice showed reduced light avoidance at estrus compared to nonestrus in two experiments designed to control for possible effects of changes in general activity. Estrous mice were quicker to enter a light chamber from a dark chamber and slower to enter a dark chamber from a light chamber, than nonestrous mice. Also, estrous mice reared up on their hind legs more frequently than nonestrous mice in the light chamber, and there was no difference between estrous and nonestrous mice in motor activity in the dark chamber. These findings, along with previous findings of reduced shock avoidance at estrus, suggest a general decrement in avoidance motivation which may be adaptive to the process of mating and which does not appear to be secondary to a change in activity level.

Effects of fructose-1,6-diphosphate administration on learning efficiency and time sense of the honey bee, apis mellifica carnica

In discrimination experiments honey bees had to decide between two glass dishes, one placed on a black cross, the other 40 cm away on a black square. In spontaneous selections the bees in 70% of all cases chose the black cross. The bees were then trained to search back and forth between the cross and the square until after 5 min sugar-water was given on the black square. Over a total of 5 learning trials, during which multiple decisions had been made by the searching insects, 96% of all choices were in favour of the black square. If 80 m M fructose-1,6diposphate (F-1,6-P 2) in 1 M glucose had been ingested by tge bees 30 min before the first spontaneous choice, learning was facilitated with 83% deciding in favour of the black square at the first trial compared with 46% of the controls (which had been fed on 1 M glucose only). In both groups of bees the same number of flight approaches was made to the cross or square as made by the bees searching for 5 min before the reward was given. Thus no change in general activity or harvesting motivation appears to be induced by F-1,6-P 2. When F-1,6-P 2 had been given at the end of a successful learning series the bees favoured the black square for up to 3 days. In contrast to the controls no new incentive needed to be given during this period. Ingestion of other metabolites proved either ineffective, as in the case of fructose-6-phosphate or 5′-adenosine monophosphate, or, as observed after feeding citrate plus 3-phosphoglycerate, even reduced the performance. To test the effect of F-1,6-P 2 on the time sense (circadian rhythm), bees were trained on three successive days to visit a feeding place at a specific time of day. The control bees which ingested only glucose on the evening of the 3rd day returned at their entrained 24-h interval on the 4th day. In contrast, the maximum frequency of appearance of bees fed on F-1,6-P 2 was advanced by one hour, with minor appearance peaks at earlier hours of the day.

Effects of increasing temperature on social behaviour in territorial groups of pumpkinseed sunfish, Lepomis gibbosus

To study the effect of thermal stress on their social behaviour, ten territorial groups of pumpkinseed sunfish, Lepomis gibbosus, were subjected to a 1°C temperature increase every other day until they succumbed. Social behaviour remained remarkably unchanged by thermal stress until nearly lethal levels. As temperature rose, ritualised behaviours increased in frequency, then fell off, probably reflecting changes in general activity. Behavioural and physiological signs of stress appeared from 31 to 38°C. Events during these social breakdowns are described and compared with the response of two other freshwater fishes with different social organisations subjected to the same thermal regime.

Prefrontal control of conditioned suppression and associated cardiovascular variables in the monkey (Macaca mulatta).

Rhesus monkeys were trained in a discriminated conditioned emotional responses paradigm. The discriminated conditioned response (CR) complex consisted of bar-press suppression, increased terminal aortic blood flow, and increased arterial pressure. Bar-press suppression and blood flow responses were temporarily eliminated by single-stage bilateral prefrontal lobectomy but not by extensive posterior cortical ablation, 2-stage prefrontal lobe removal, or 3-stage prefrontal cortical surface ablation. The blood pressure CR was attenuated by almost every surgical operation. The changes in heart rate paralleled changes in general activity. These data indicate that the prefrontal lobes influence the conditioned suppression of ongoing rewarded behavior and the vascular responses accompanying the suppression. The time course for recovery of the somatic CR after lobectomy differed from those of the cardiovascular CRs.

Heart rate changes in dogs during temporally spaced responding

Heart rate (HR) and general activity were recorded while dogs pressed a panel for food on a differential reinforcement of low rate schedule. In Experiment 1, 2 of the 4 dogs showed an acceleration of HR prior to panel presses, while all dogs decelerated after panel presses. The magnitude of HR deceleration, however, was not different for reinforced and non-reinforced (error) responses. The same general HR pattern was observed in Experiment 2 in which the peak acceleration coincided with panel presses for two dogs and slightly afterwards for two dogs. For 3 of the 4 dogs in Experiment 2, a significant correlation was found between HR and general activity changes. While the results supported the notion that metabolic requirements generated by a particular behavioral task are a primary determinant of behaviorally induced HR changes, they failed to support Malmo's contention that HR changes reflect the reinforcement process.

Response rate for food and water in the rat as a function of noncontingent, reinforcing septal stimulation

Rats with electrodes in the septal region of the brain received noncontingent, reinforcing stimulation while bar pressing for food and for water on variable ratio schedules. Rate of pressing for water was found to be significantly reduced as a function of intracranial stimulation. No significant differences were found between stimulation and nonstimulation periods for Ss reinforced with food. The data revealed no change in general activity as a function of the electrical stimulation.

Direct observation of the rat's activity during food deprivation

Abstract The significance of changes in general activity under deprivation has been obscured by the fact that different recording devices yield discrepant results. By adopting a time-sampling procedure, it was feasible to make direct visual observation of 24 male white rats (ages 46–54 or 128–138 days) over several days. During ad libitum ingestion the animals were most frequently classified as “resting”—80% of the time in the light and 40% in relative dark (far-red illumination). During continuous food deprivation resting was much less frequently noted, and there was a marked increase in head movement and locomotion about the cage. These trends were slightly the more distinct in the younger group. The results appear to be consonant with an arousal conception of drive.