Effects of peptides on animal and human behavior: a review of studies published in the first twenty years of the journal Peptides.

This review catalogs effects of peptides on various aspects of animal and human behavior as published in the journal Peptides in its first twenty years. Topics covered include: activity levels, addiction behavior, ingestive behaviors, learning and memory-based behaviors, nociceptive behaviors, social and sexual behavior, and stereotyped and other behaviors. There are separate tables for these behaviors and a short introduction for each section.     

Effect of vasopressin on open field and activity behavior of the vasopressin-deficient (Brattleboro) rat

The effect of 1 and 5 micrograms AVP injections on open field and photoactivity chamber behavior of D.I. and normal Long-Evans animals was studied. Administration of 5 micrograms AVP (SC) resulted in a statistically significant depression of both open field and photochamber activity in the D.I. rat, but had a less pronounced effect on normal animals. However, 1 microgram AVP resulted in only minor alterations of activity in both D.I. and normal animals. In terms of learned behavior, D.I. and normal animals displayed similar within-session habituation when comparisons were made following the same treatment conditions. Thus, this study supports the hypothesis that vasopressin may influence memory tasks by modulation of related states of emotionality, motivation, and/or attention rather than by direct involvement in the retrieval and/or consolidation of information.     

Effects of peptides, with emphasis on feeding, pain, and behavior A 5-year (1999-2003) review of publications in Peptides

Novel effects of naturally occurring peptides are continuing to be discovered, and their mechanisms of actions as well as interactions with other substances, organs, and systems have been elucidated. Synthetic analogs may have actions similar or antagonistic to the endogenous peptides, and both the native peptides and analogs have potential as drugs or drug targets. The journal Peptides publishes many leading articles on the structure–activity relationship of peptides as well as outstanding reviews on some families of peptides. Complementary to the reviews, here we extract information from the original papers published during the past five years in Peptides (1999–2003) to summarize the effects of different classes of peptides, their modulation by other chemicals and various pathophysiological states, and the mechanisms by which the effects are exerted. Special attention is given to peptides related to feeding, pain, and other behaviors. By presenting in condensed form the effects of peptides which are essential for systems biology, we hope that this summary of existing knowledge will encourage additional novel research to be presented in Peptides.     

Effects of Conus peptides on the behavior of mice

When different cone snail peptides are injected into the CNS of vertebrates, they elicit diverse behaviors primarily because of their selectivity for specific receptor or ion channel subtypes. The subcellular context of the highly localized targets (i.e. the presence of other cellular elements that are functionally linked to the targets of conopeptides) is another determinant of the elicited behavior. Recent studies have advanced our understanding of the mechanisms by which four conopeptides produce different behaviors in mice.     

Effects of peptides: a cross-listing of peptides and their central actions published in the journal Peptides from 1994 through 1998.

Effects of peptides on the central nervous system are presented in two ways so as to provide a cross-listing. In the first table, the peptides are listed alphabetically. In the second table, the central nervous system effects are arranged alphabetically. No longer can there be any doubt that peptides affect the central nervous system, sometimes in several ways.     

Effects of metals on fish behavior: a review

Synopsis Behavioral toxicity tests, if properly designed, can be used in conjunction with standard acute lethality tests, chronic full or partial life cycle tests, and early life stage toxicity tests to add ecological realism to toxicant assessments and the regulations made as an outgrowth of these assessments. Changes in certain fish behaviors, especially cough rate and avoidance reactions, are very sensitive indicators of sublethal exposure to metals. Other tests involving predator avoidance, feeding behavior, learning, social interactions, and a variety of locomotor behaviors show promise but have been insufficiently studied to judge their sensitivity or utility. No behavioral tests have been standardized and few have been verified in the field. We discuss the behavioral tests that have been used with metals, examine their sensitivity compared with standard laboratory toxicity tests, and assess the potential ecological significance of the behavioral changes observed.Journal Paper No. .1-11959 of the Iowa Agriculture and Home Economics Experiment Station, Ames, IA 50011. U.S.A. Project No. 2627.     

Effect of oral diazepam on feeding behavior and activity of Hawai’i ’amakihi (Hemignathus virens)

Feeding behavior and activity during captivity were studied in wild-caught Hawai’i ’amakihi, Hemignathus virens, to evaluate diazepam's hyperphagic and anxiolytic effects. Birds were captured in mist nets, given either oral diazepam (1 mg/kg) or an equivalent volume per weight of lactated Ringer's solution orally, and held in captivity for 6 h. Thirteen-minute focal animal samples were videotaped at the beginning of each hour. Feeding behaviors, grooming and picking events, changes in position, and body weights were recorded. Mean duration of feeding, percentage of time spent feeding, and number of feeding events were significantly higher for treatment birds than for controls, and significantly increased over time. Feeding duration was significantly correlated to weight change. Weight change was not significantly different between groups, but on average treatment birds lost less weight than control birds. No significant differences in grooming behaviors were found between the groups, but there was a session effect of increased grooming over time in both groups. Also, a significant session effect in movement events was apparent, with control birds becoming less active and treatment birds becoming more active over time. Results indicate diazepam increased feeding behaviors and movement in this passerine species during a short period of captivity.     

Flavonoids and cognitive function: a review of human randomized controlled trial studies and recommendations for future studies

Evidence in support of the neuroprotective effects of flavonoids has increased significantly in recent years, although to date much of this evidence has emerged from animal rather than human studies. Nonetheless, with a view to making recommendations for future good practice, we review 15 existing human dietary intervention studies that have examined the effects of particular types of flavonoid on cognitive performance. The studies employed a total of 55 different cognitive tests covering a broad range of cognitive domains. Most studies incorporated at least one measure of executive function/working memory, with nine reporting significant improvements in performance as a function of flavonoid supplementation compared to a control group. However, some domains were overlooked completely (e.g. implicit memory, prospective memory), and for the most part there was little consistency in terms of the particular cognitive tests used making across study comparisons difficult. Furthermore, there was some confusion concerning what aspects of cognitive function particular tests were actually measuring. Overall, while initial results are encouraging, future studies need to pay careful attention when selecting cognitive measures, especially in terms of ensuring that tasks are actually sensitive enough to detect treatment effects.     

Central nervous system effects of peptides, 1980-1985: a cross-listing of peptides and their central actions from the first six years of the journal Peptides

A tabular synopsis is presented for articles concerned with the effects of peptides on the central nervous system that appeared in the journal Peptides from 1980-1985. A table arranged alphabetically by peptide and one arranged by effects, both listing routes of injection, species, direction of change, and qualifying notes, provides easy cross-referencing of peptides and their effects. Over 80 peptides and over 135 effects are listed. The list of peptides includes, but is not limited to: ACTH, angiotensin, bombesin, bradykinin, calcitonin, casomorphin, CCK, ceruletide, CGRP, CRF, dermorphin, DSIP, dynorphin, endorphins, enkephalins, GRF, gastrin, LHRH, litorin, metkephamid, MIF-l, motilin, MSH, NPY, NT, oxytocin, ranatensin, sauvagine, substances P and K, somatostatin, TRH, VIP, vasopressin, and vasotocin. The list of effects includes, but is not limited to: aggression, alcohol, analgesia, attention, avoidance, behavior, cardiovascular regulation, catalepsy, conditioned behavior, convulsions, dopamine binding and metabolism, discrimination, drinking, EEG, exploration, feeding, fever, gastric secretion, GI motility, grooming, learning, locomotor behavior, mating, memory, neuronal activity, open field, operant behavior, rearing, respiration, satiety, scratching, seizure, sleep, stereotypy, temperature, thermoregulation and tolerance.     

Effects of single or repeated dermal exposure to methyl parathion on behavior and blood cholinesterase activity in rats

The effects of a single or repeated dermal administration of methyl parathion on motor function, learning and memory were investigated in adult female rats and correlated with blood cholinesterase activity. Exposure to a single dose of 50 mg/kg methyl parathion (75% of the dermal LD(50)) resulted in an 88% inhibition of blood cholinesterase activity and was associated with severe acute toxicity. Spontaneous locomotor activity and neuromuscular coordination were also depressed. Rats treated with a lower dose of methyl parathion, i.e. 6.25 or 12.5 mg/kg, displayed minimal signs of acute toxicity. Blood cholinesterase activity and motor function, however, were depressed initially but recovered fully within 1-3 weeks. There were no delayed effects of a single dose of methyl parathion on learning acquisition or memory as assessed by a step-down inhibitory avoidance learning task. Repeated treatment with 1 mg/kg/day methyl parathion resulted in a 50% inhibition of blood cholinesterase activity. A decrease in locomotor activity and impairment of memory were also observed after 28 days of repeated treatment. Thus, a single dermal exposure of rats to doses of methyl parathion which are lower than those that elicit acute toxicity can cause decrements in both cholinesterase activity and motor function which are reversible. In contrast, repeated low-dose dermal treatment results in a sustained inhibition of cholinesterase activity and impairment of both motor function and memory.     

Action of two corpus cardiacal peptides on muscles of the hindgut of Periplaneta americana L. (Orthoptera: Blattidae)

1. (1) Two small, basic peptides (Ic and II) which stimulate muscles of the hindgut, but not the heart, have been separated from extracts of the corpora cardiaca by ion exchange chromatography and gel filtration.

2. (2) Results obtained with the 5-HT antagonist mianserin hydrochloride suggest that both peptides stimulate contractions of the hindgut by direct action without mediation by an indoleamine such as 5-HT.

3. (3) Extracellular calcium ions are required for rapid contractions of the hindgut stimulated by peptides Ic and II. However, the tonus response to these peptides does not appear to depend on the same inward transmembrane transport of extracellular Ca²⁺ as rapid contractions.

4. (4) Theophylline (5 mM) potentiated the action of both peptides on hindgut muscle, however, stimulation of hindgut muscle by cardiacal extract did not cause a significant increase in the level of cyclic AMP as compared with controls.

5. (5) These results more clearly define the number, character and possible action of cardiacal peptides stimulating hindgut muscle in P. americana.

     

Neural tube defects: a review of human and animal studies on the etiology of neural tube defects

Although neural tube defects are a common congenital anomaly, their etiology is not known. Human studies have emphasized the pathology and epidemiology of the defects and suggest that in the majority of cases the etiology is multifactorial. Factors which appear possibly to be important are genetic predisposition, maternal illness, and fetal drug exposure. Animal studies have utilized naturally occurring neural tube defects and teratologically induced lesions. No animal model has been convincingly established as the equivalent of human neural tube defects. However, animal models have allowed investigation of the mechanisms of suggested human teratogens and determination of the pathogenesis of naturally occurring animal defects. Their most important contribution has been in furthering the understanding of the normal mechanisms of neural tube closure. It may be through this understanding that the etiology of human neural tube defects will be determined.     

Fusarium mycotoxins: a review of global implications for animal health, welfare and productivity

Trichothecenes, zearalenone (ZEN) and fumonisins are the major Fusarium mycotoxins occurring on a worldwide basis in cereal grains, animal feeds and forages. Other important Fusarium mycotoxins include moniliformin and fusaric acid. Spontaneous outbreaks of Fusarium mycotoxicoses have been recorded in Europe, Asia, New Zealand and South America and, in addition, chronic exposure occurs on a regular and more widespread scale. The metabolism and adverse effects of the Fusarium mycotoxins are considered in this review with particular reference to recent data on specific and proposed syndromes and to interactions among co-occurring mycotoxins. Within the trichothecene group, deoxynivalenol (DON) is associated with emesis, feed refusal and depressed feed intake in pigs, while T-2 toxin and diacetoxyscirpenol (DAS) are now clearly linked with oral lesions in poultry. The gut microflora of farm livestock are able to transform DON to a de-epoxy derivative. In contrast, the ovine metabolism of ZEN results in the production of five metabolites and relatively high levels of these forms may be excreted in the urine as glucuronides. There is now undisputed evidence that ZEN and its metabolites possess estrogenic activity in pigs, cattle and sheep, but T-2 toxin has also been implicated in reproductive disorders in farm livestock. Fumonisins are positively linked with pulmonary edema in pigs, leukoencephalomalacia in equines and with deranged sphingolipid metabolism in these animals. Fusarium mycotoxins have also been provisionally implicated in ovine ill-thrift, acute mortality of poultry and in duodenitis/proximal jejunitis of horses. Several Fusarium mycotoxins may co-occur in a particular feed ingredient or in compound feedingstuffs. In general, combinations of Fusarium mycotoxins result in additive effects, but synergistic and/or potentiating interactions have been observed and are of greater concern in livestock health and productivity. Synergistic effects have been reported between DON and fusaric acid; DON and fumonisin B₁ (FB₁); and DAS and the Aspergillus-derived aflatoxins. Limited evidence of potentiation between FB₁ and DON or T-2 toxin has also emerged recently. Additive and synergistic effects between known and unidentified mycotoxins may account for enhanced adverse effects observed on feeding Fusarium-contaminated diets. The potential for transmission of DON into eggs and of ZEN into porcine kidney and liver has been demonstrated. However, lactational carry-over of FB₁ appears not to occur, at least in cows and sows. It is concluded that livestock health, welfare and productivity may be severely compromised by consumption of DON, T-2 toxin, DAS, ZEN and fumonisins and by interactions among these mycotoxins. Safety of some animal products may also be at risk. Furthermore, in view of the limited options available for remediation, it is concluded that exploitation of crops resistant to Fusarium infection offers the most viable strategy for reducing mycotoxin contamination of grain and animal feed.     

Caenorhabditis elegans: Effects of 5-hydroxytryptophan and dopamine on behavior and development

5-Hydroxytryptophan (5-HTP) was introduced iontophoretically into the vulva region of Caenorhabditis elegans to examine behavioral responses to this putative neurotransmitter. Responses in esophageal basal bulb pulsation and/or vulval contractions occurred. Little relation was observed between dosage and behavioral response. Similar behavioral responses followed topical applications of 5-HTP. An inverse relationship between the rates of esophageal pumping and vulval contraction was recorded following both iontophoretic injection and topical application. Following iontophoretic application, young nematodes resumed body movement sooner than old nematodes did. Growth significantly increased when 5-HTP or dopamine was added to the culture medium, but neither chemical influenced fecundity or life span.     

Puberty as a critical risk period for eating disorders: A review of human and animal studies

This article is part of a Special Issue “Puberty and Adolescence”.     

Effects of lesion of the inferior olivary complex by 3-acetylpyridine on learning and memory in the rat

Summary DA/HAN-strained male rats (pigmented rats) were submitted to two experimental tasks consisting of spatial learning (water-escape) and a passive avoidance conditioning. Both these tasks were performed by different animals. In order to destroy the inferior olivary complex, the animals were injected with 3-acetylpyridine either 9 days prior to the initial learning session or 24 h after completion of the learning task. They were retested (retrieval test) 10 days after the initial learning was achieved. Learning and retention were compared to those noted in control rats. Administration of 3-acetylpyridine before the initial learning did not prevent the spatial learning but the scores were greatly altered and the number of trials needed to reach the fixed learning criterion was much greater than in controls. However, 10 days later the animals had memorized their initial experience. Injection of 3-acetylpyridine after the initial learning session impaired memory: the animals had completely forgotten their initial learning. It can therefore be concluded that lesion of the afferent climbing fibres to the cerebellar cortex alters learning and retention of a spatial task. Such a lesion does not interfere with learning and retention of a passive avoidance conditioning, since in this condition the experimental animals injected with 3-acetylpyridine either before or after the initial learning behave similarly to controls. The effects of the inferior olivary complex lesion are obviously different according to the task to be learnt, suggesting that these two tasks do not require the integrity of the same nervous structures.Abbreviations 3-AP 3-acetylpyridine - C control - ILR initial learning-lesion-retrieval - IOC inferior olivary complex - LIR lesion-initial learning-retrieval     

Investigations on training, recall and reversal learning of a Y-maze by dwarf goats (Capra hircus): the impact of lateralisation

We investigated maze learning in dwarf goats (Capra hircus) and the impact of lateralisation on learning. Lateralisation refers to the collection of phenomena in which external stimuli are perceived and processed differentially on the two sides of the brain and/or certain behaviours are preferentially performed by one side of the body. We trained 29 dwarf goats in a Y-maze, directing them to the opposite alley from that chosen in a free pre-run. In total, 13 goats were trained to the left alley (L-goats) and 16 goats to the right alley (R-goats). Recall of the trained alley was tested three months later. We then analysed reversal learning across 10 reversals. During training, the direction of the alley had an impact on learning. The number of runs required to reach the learning criterion was significantly lower in the L- than the R-goats. The goats recalled the trained alley three months later, with no difference between the L- and the R-goats. During the reversal learning, the reversal only tended to impact learning performance, whereas the directions of the new and the initially trained alley did not. Goats did not adopt a general rule with which to master the maze (e.g., win-stay/lose-shift) across the 10 reversals. Our results indicate a right hemisphere bias in the processing of visuospatial cues in the maze during initial training; however, no such impact was detected during reversal learning.     

Exploring human interaction and diet effects on the behavior of dogs in a public animal shelter

This study examined the effects of 2 manipulations-a brief, regular period of human contact and diet-on the behavior of dogs confined in a public animal shelter. A behavioral battery designed to assess reactions to novel situations, and a test of responsiveness to an unfamiliar human were administered both prior to (pretest) and immediately following (posttest) the 8-week intervention period. Overall, the regular periods of increased human contact together with a diet that contained augmented levels of digestible protein, fat, calories, and animal-derived ingredients reduced signs of behavioral reactivity from pretest to posttest. In some cases, the comparison diet appeared more effective, but only for dogs receiving minimal human interaction. The results indicate that a combination of human interaction and high quality diet may positively affect the behavior of dogs in animal shelters.