CRF-induced excessive grooming behavior in rats and mice

We studied the grooming response to lateral ventricle injection of CRF in both rats and mice under similar conditions. One microgram of CRF ICV induced a pronounced increase (3- to 4-fold) in the frequency of self-grooming in rats, but only a much smaller (less than 20%) increase in mice. The minimum effective dose of CRF in rats was 300 ng. Although ACTH1-24 induced less grooming in mice than in rats, the difference in potency did not appear to be sufficient to explain the differences between the effectiveness of CRF in the two species. Whereas ACTH increased all types of grooming scored. CRF increased all forms of grooming except flank scratching with the hind limb. The major effect of CRF was to increase the number of episodes of grooming, whereas ACTH1-24 tended to prolong the length of individual episodes. The excessive grooming induced by ICV CRF was not affected by prior treatment with dexamethasone, suggesting that the increased grooming was not due to secondary release of ACTH from the pituitary. Nevertheless, ICV CRF might induce grooming by releasing MSH/ACTH from cerebral storage sites. CRF-induced grooming, like ACTH-induced grooming, was inhibited by naloxone pretreatment. Despite the small qualitative differences, CRF-induced grooming could be due to secondary release of ACTH.     

Intranasal administration of testosterone increased immobile-sniffing, exploratory behavior, motor behavior and grooming behavior in rats

Currently, testosterone (T) replacement therapy is typically provided by oral medication, injectable T esters, surgically implanted T pellets, transdermal patches and gels. However, most of these methods of administration are still not ideal for targeting the central nervous system. Recently, therapeutic intranasal T administration (InT) has been considered as another option for delivering T to the brain. In the present study, the effects of 21-day InT treatment were assessed on open field behavior in gonadectomized (GDX) rats and intact rats. Subcutaneous injections of T at same dose were also tested in GDX rats. A total of 12 behavioral events were examined in GDX groups with or without T and in intact groups with or without InT. Significant decreases in open field activity were observed in rats after GDX without InT compared to sham-operated rats. The open field activity scores for most tests significantly increased with InT treatment in GDX rats and in intact rats compared with the corresponding GDX rats and intact rats. Intranasal administration of T improved the reduced behaviors resulted from T deficiency better than subcutaneous injection of T, demonstrating that T can be delivered to the brain by intranasal administration. Our results suggest that intranasal T delivery is an effective option for targeting the central nervous system.     

Studies on bombesin-induced grooming in rats

The gross behavior induced by centrally administered bombesin in rats was compared to that elicited by ACTH-(1–24) and the somatostatin analog, des AA^{1,2,4,5,12,13}[D-Trp⁸]-somatostatin (ODT8-SS). Bombesin (0.001–1 μg, ICV) caused dose-related excessive scratching which was qualitatively different from that associated with the other two groom-inducing agents. Bombesin-induced grooming was not markedly affected by behaviorally nondepressant doses of haloperidol, morphine, naloxone or neurotensin. Bombesin was active in genetically hypotrichotic (essentially furless) rats; and, again in such animals, even after numbing the area caudal to the shoulders with lidocaine. Tolerance and cross-tolerance studies with bombesin and ODT8-SS indicated that they produce scratching through different mechanisms. Bombesin caused scratching when injected directly into the periaqueductal gray, but not when administered intravenously. Neither hypophysectomy nor adrenalectomy markedly affected bombesin-induced grooming. This behavior appears to be initiated in the central nervous system and is produced independently of the pituitary-adrenal axis.     

Quantitative observations of grooming behavior in free-rangingMacaca mulatta

Quantitative methods of observation and analysis were used in a 12-month study of grooming behavior of free-rangingMacaca mulatta on La Cueva Island at La Parguera, Puerto Rico. Observations lasting 30–120 minutes were made from eight positions on the island at a standard time of day when monkeys were either feeding or resting. Two dependent variables were obtained: (1) the number of monkeys present in the observation area were noted by age and sex class at five-minute intervals throughout each observation, and (2) the frequency of grooming encounters was tabulated by the age and sex class(es) of groomer and recipient. These data were computed as grooms/hour/possible interacting combination of monkeys. Grooming frequencies were higher in non-feeding situations than when monkeys were feeding. The largest social group had the lowest mean grooming rates, while the smallest group had the highest grooming frequencies. More grooming occurred during the November-to-February mating season than at other periods of the year. Adult females were involved in over 60% of all grooming behavior, juveniles participated in 25% of the grooming, while adult males groomed females, primarily during the mating season, and rarely groomed other males or juveniles. Genealogical relationships, levels of group aggression and the feeding or resting context all influenced the frequency of grooming. This study provides support for the hypothesis that the basic social unit for rhesus macaques consists of a core of adult females with their juvenile and infant progeny.     

Mechanisms underlying intracisternal TRH-induced stimulation of gastric acid secretion in rats

The neurohumoral pathways mediating intracisternal TRH-induced stimulation of gastric acid secretion were investigated. In urethane-anesthetized rats, with gastric and intrajugular cannulas, TRH or the analog [N-Val2]-TRH (1 microgram) injected intracisternally increased gastric acid output for 90 min. Serum gastrin levels were not elevated significantly. Under these conditions the TRH analog, unlike TRH, was devoid of thyrotropin-releasing activity as measured by serum TSH levels. In pylorus-ligated rats, gastrin values were not modified 2 h after peptide injection whereas gastric acid output was enhanced. TRH (0.1-1 micrograms) stimulated vagal efferent discharge, recorded from a multifiber preparation of the cervical vagus in urethane-anesthetized rats and the response was dose-dependent. The time course of vagal activation was well correlated with the time profile of gastric stimulation measured every 2 min. These results demonstrated that gastric acid secretory stimulation elicited by intracisternal TRH is not related to changes in circulating levels of gastrin or TSH but is mediated by the activation of efferent vagal pathways that stimulated parietal cell secretion.     

Descending neurons coordinate anterior grooming behavior in Drosophila

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Corticotrophin releasing factor,grooming and ingestive behavior

Corticotrophin releasing factor (CRF) decreases food intake after starvation and during the nocturnal feeding phase in rats. This decrease appears to be associated with CRF producing a marked increase in grooming. The effects of CRF on food intake and grooming are independent of its effects on the pituatary. CRF is a putative mediator of stress-induced anorexias.     

A comparison of grooming behavior potencies of neurohypophyseal nonapeptides

We have previously demonstrated that intracerebroventricular (ICV) administration of oxytocin (OXY) enhanced grooming behaviors in male and female rats at a 1 microgram dose. In the present study female rats were injected ICV with 1 microgram OXY or equimolar doses of other peptides. At this dose arginine-vasopressin (AVP), arginine-vasotocin (AVT) and lysine-vasopressin (LVP), as well as alpha-MSH, were as effective as OXY in increasing grooming behavior. At equimolar doses, ACTH1-10, tocinoic acid (the ring structure of OXY) and Pro-Leu-Gly-NH2 (the tail structure of OXY) had no significant effect on grooming behavior. The potency of AVP and AVT was determined across a 0.05-5 microgram dose range. Grooming scores increased in an apparent linear manner across a similar OXY dose range. Both AVP and AVT, however, manifested an inverted U grooming response curve. Maximum grooming scores resulted from a 0.1 microgram dose of AVT or a 0.5 microgram AVP dose. Analyses of the aspects of grooming separately found that nonapeptides OXY, AVP and AVT all elevated body grooming, washing, and scratching. Because AVT and AVP administration resulted in grooming scores significantly higher than OXY at lower doses, we concluded that the CNS is more sensitive to the effects of AVT and AVP on grooming behavior than OXY.     

Abdominal grooming in the cockroach: Development of an adult behavior

Chemical or tactile irritants delivered to the dorsomedial region of the abdomen of the cockroach Periplaneta americana. evoke a complex grooming response. In larvae the response consitsts of extension of all six legs and arching of the abdomen which is rubbed against any solid surface presented. In adults, leg extension and arching are accompanied by side to side wagging of the abdomen and rapid scissoring of the wings.In some decapitated late instar larvae, abdominal wagging behavior can be evoked by chemical or tactile stimulation of the dorso-medial region of the abdomen. The form of the wag is somewhat different in these animals than in the adults, and it occurs at a lower frequency.Neuronal circuitry underlying the rhythmic wagging response of the adult may therefore be laid down or made functional in the mid- to late-larval stages. The wagging behavior is not normally expressed until the final ecdysis.A population of sensory setae is found on the abdomen at all stages of development, and some of these are presumed to trigger the grooming behavior when stimulated. The morphology and distribution of some of the adult receptors differs from some of the larval receptors.All larvae, including those late-instar individuals which show an adult-like response (wagging) have identical receptors on the abdomen in terms of morphology, distribution, and general responsiveness. Thus, no obvious changes in abdominal sensory receptors are correlated with the emergence of the wagging behavior. Anatomical and/or functional changes within the central nervous system are most likely responsible for the emergence of adult wagging behavior.     

Cyclic analogs of ACTH fragments in self-stimulation and grooming behavior in rabbits

In present study new cyclic fragments of ACTH EHFRWGKPVG--NH2 and KHFRWG--NH2 were investigated in organization of self-stimulation and grooming behaviour in rabbits. Intracerebroventricular injections of EHFRWGPVG--NH2 in doses of 0.1-2.5 g evoked significant increases of self-stimulation and in doses of 4-5 g suppressed self-stimulation in rabbits. The effect of other fragments KHFRWG--NH2 on self-stimulation was not statistically significant. Both fragments induced excessive grooming behaviour in rabbits. The effects of these fragments persisted of 48-72 hours.     

Hoxb8 is required for normal grooming behavior in mice.

Repertoires of grooming behaviors critical to survival are exhibited by most animal species, including humans. Genes that influence this complex behavior are unknown. We report that mice with disruptions of Hoxb8 show, with 100% penetrance, excessive grooming leading to hair removal and lesions. Additionally, these mice excessively groom normal cagemates. We have been unable to detect any skin or PNS abnormalities in Hoxb8 mutants. These observations suggest that the excessive, pathological grooming exhibited by these mice results from CNS abnormalities. Consistent with this interpretation, we demonstrate Hoxb8 expression in regions of the adult mouse CNS previously implicated in the control of grooming. The aberrant behavior observed in Hoxb8 mutants is not unlike that of humans suffering from the OC-spectrum disorder, trichotillomania. Interestingly, Hoxb8 is expressed in regions of the CNS known as the "OCD-circuit."     

Nonspecific grooming in rats during the solution of an extrapolation task

Grooming behavior in laboratory brown rats was analysed in the course of extrapolation task solving. Cases of task solution (correct and incorrect) were compared with those when animal "refused" to turn round the screen during search of food bait. In latter cases grooming episodes were more numerous, their latency and duration being higher than during former cases. At the same time the latest stages of experiment (when 8-13 trials a day twice a week were presented) were characterized by more frequent grooming occurrence as well as by longer latencies and duration of grooming episodes. When rats were given I trial a day with one week intervals grooming incidence as well as "refusals" occurrence decreased. The possible participation of animal grooming in arranging the defense reactions against excessive and inadequate activity is discussed.     

Graphic registration of grooming behavior and its parameters in rat ontogenesis]

Ontogenic development of grooming behaviour (washing, scratching, lacking, shake down) by using precise graphic recording was studied. For this reason actograph with crystal pickup and electroencephalograph were used. A rhythmic phase of grooming behaviour is formed gradually, reaching the adult level up to the period in 16-17 days.     

Individual typologic characteristics of the open-field behavior of rats

By means of ethograms record and analysis, connection has been studied between the properties of rats behaviour organization in the open field, determining the level of behaviour entropy in this test, and the speed of conditioned reflexes formation in the Skinner chamber. According to behaviour entropy level the rats are significantly divided into four groups; the lowest speed of conditioned reflexes formation in the Skinner's chamber is observed in the animals of the first (low entropy) group, the highest--in the fourth (high entropy) group. The obtained data are discussed according to Pavlov's concepts on the characteristics of the basic nervous processes, determining individual-typological characteristics of the higher nervous activity of the animal. Conclusion is made that division according to the level of behaviour entropy in the open field test may serve as a safe method of express-estimation of the animals abilities to conditioned habits formation.     

Social grooming and play behavior of a captive group of chimpanzees

Aspects of the social grooming and play behavior of a group of six adolescent and young adult chimpanzees are contrasted and compared. Eleven months’ data indicate that older chimpanzees groomed more and played less than younger individuals. This transition period occurred earlier for females than males. Grooming behavior appeared to vary with reproductive state. A positive correlation was found between the estrous condition of cycling females and the amount of grooming that they received from the males. A mother of a young infant received particularly high levels of grooming from the other group members. Less variation among individuals was found for frequencies of play as compared to grooming. Play dropped following the death of one individual and was entirely inhibited for three weeks following the group’s transfer to a new environment and the reintroduction of a former group member. Comparison to a free-ranging population indicates important differences in both frequencies and general patterns of play and grooming.     

Alpha MSH-induced excessive grooming behavior involves a GABAergic mechanism.

It has been shown that MSH administered in the ventral tegmental area (VTA) elicits excessive grooming behavior (EGB) by stimulating an acetylcholinergic pathway. The present work was performed in order to evaluate the possible participation of the GABAergic system in this behavior. VTA injection of GABA antagonist bicuculline stimulated the EGB (55.5 +/- 2.4). In contrast, this effect disappeared if the animals were pretreated with atropine (33.1 +/- 1.5). When bicuculline was injected before a 200 ng/microliters dose of MSH, the EGB increased (87.6 +/- 4.4) in comparison to MSH-treated rats (46.5 +/- 3.2). Our results suggest that GABA, ACh, and MSH interact in the VTA in the induction of EGB; an increase in MSH levels appears to stimulate cholinergic neurons. GABAergic fibers probably modulate the cholinergic discharge at the presynaptic level.     

Effects of ketanserin on DOI-, MCPP- and TRH-induced prolactin secretion in estrogen-treated rats.

The effects of ketanserin (Ket), a serotonin (5-HT2) receptor antagonist, on DOI- and mCPP-, two 5-HT agonists, and TRH-induced PRL secretion were studied. Adult female Sprague-Dawley rats ovariectomized for two weeks and treated with a long-acting estrogen, polyestradiol phosphate for one week were used. Drug administration and serial blood sampling were accomplished through indwelling intraatrial catheters which were implanted two days before the experiment. Both DOI (0.5 mg/kg BW) and mCPP (1 mg/kg BW) stimulated prolactin secretion within 10 min after iv injection and the effects were diminished by 30 min. In animals pretreated with Ket (5 mg/kg BW, sc), the effect of DOI was blocked, while that of mCPP was augmented. Co-administration of Ket (1 mg/kg BW, iv) with DOI or mCPP produced similar effect. Pretreatment with Ket, similar to sulpiride (Sulp), a dopamine antagonist, potentiated the TRH-induced prolactin secretion. Co-administration of Ket and Sulp further potentiated the TRH action. It is concluded that Ket not only acts as a 5-HT2 receptor antagonist that blocks the action of DOI, but may also act on dopamine receptor(s) with lower sensitivity to Sulp.     

Description of the behavior of praying mantis with particular reference to grooming

Eighteen behavior patterns, encompassing most of the observable behavior of individually housed praying mantids, Sphodromantis lineola, were recorded using a point sampling technique. The data were sorted into four major behavioral categories: (1) food acquisition, (2) grooming, (3) inactivity, and (4) locomotion and miscellaneous. The mantids spent most of the time in an inactive state, which is consistent with their way of life as ambushing predators. Most of the animals' active time was spent in food acquisition (60%). Grooming behaviors comprised 16.7% of the active time; foreleg grooming represented 82% of grooming, while head grooming represented 14.3%. Analysis of the behavioral states in close temporal proximity to head grooming indicated that head grooming often follows foreleg grooming, occuring in bouts of about 1/2 to 1 min duration. Foreleg grooming is also closely associated with eating and seems to represent a pivotal behavior pattern between food acquisition and grooming, possibly sharing causal factors with both.