Interactions between histamine H1 and H3 and dopamine D1 receptors on feeding behavior in chicken

Background: brain monoamines [such as histamine and dopamine] play an important role in emotions, cognition, reward and feeding behavior. The interactions between histamine and dopamine were studied in many physiological functions but this correlation is unclear in feeding behavior of chickens

Objectives: the aim of this study was to investigate the interaction of central histaminergic and dopaminergic systems on food intake in broiler chicken

Methods: in this study intracerebroventricular [ICV] injection was used for manipulation of histaminergic and dopaminergic systems. In Experiment 1, 3 h-fasted chicks were given an ICV injection of histamine, SCH23390, a D1 receptors antagonist and co-injection of histamine and SCH23390. Experiments 2-5 were similar to experiment 1 except birds were injected with AMI-193, D2 receptors antagonist; NGB2904, D3 receptors antagonist; L-741,742, D4 receptors antagonist and 6-OHDA, 6-hydroxydopamine instead of SCH 23390, respectively. In experiment 6, ICV injection of dopamine, chlorpheniramine, H1 receptors antagonist and co-administration of dopamine and chlorpheniramine were done. Experiments 7-9 were similar to experiment 6, except birds ICV injected with famotidine, H2 receptors antagonist; thioperamide, H3 receptors antagonist and alpha-FMH, alpha-fluoromethylhistidine in place of chlorpheniramine, respectively. Then cumulative food intake [g] was measured at 30, 60 and 120 min after the injection

Results: histamine decreased food intake compared to the control chicks indicating an inhibitory effect of histamine on food intake and SCH23390 attenuated the effect of histamine on food intake [p<0.001]. In addition, hypophagic effect of histamine decreased by 6-OHDA [p<0.001]. Chlorpheniramine and alpha-FMH significantly attenuated dopamine induced hypophagia [p<0.001]. However, thioperamide amplified the inhibitory effect of dopamine on food intake [p<0.001]

Conclusions: these results suggest there is relationship between histaminergic and dopaminergic systems on food intake in chicken and H1, H3 and D1 receptors are involved in this interaction

[ role of 5-HT[2A] and 5-HT[2c] receptors on harmaline-induced eating behavior in 24-h food-deprived broiler cockerels]

This study was designed to examine the effects of intracerebroventricular [ICV] injection of ketanserin [5-HT[2a] receptor antagonist] and SB242084 [5-HT[2c] receptor antagonist] on harmaline induced feeding and drinking response in 24-h food-deprived [FD24] broiler cockerels. At first, guide cannula was surgically implanted in the right lateral ventricle of chickens. In experiment 1, birds were injected intracerebroventriculary with 0, 25, 50 and 100 microg of harmaline. In experiment 2, chickens received 10 microg ketanserin prior to the injection of harmaline. In experiment 3, birds were administered with harmaline after 3 microg SB242084 and the cumulative food and water intake was determined at 3 h post injection. The results of this study showed that harmaline decreases food consumption and increases water intake in FD24 broiler cockerels [P

[ morphometrical study of testis and histometrical study of seminiferous tubules in Coenzyme Q10 fed ostriches]

Nowadays, Coenzyme Q10 is used in male infertility treatment as an oral or injectable supplement. The main role of coenzyme Q10 is presence in the electron transport chain during cellular respiration process to produce energy in the mitochondrial membrane. The purpose of the current study was to evaluate the effects of Coenzyme Q10 on morphological characteristics of the testis and histological features of seminiferous tubules in ostrich. 18 male ostriches, 6 months old, from South African breed [struthio camelus australis] were selected and divided into three groups of 6. Group one [control] was fed only by maintenance ration. The second group received 10 mg/kg and the third one, 20mg/kg of Coenzyme Q10 in their food. Coenzyme was given orally and once daily. After two months, the birds were slaughtered and gonadosomatic index [GSI], weight, height and diagonal of testis, diameter of the seminiferous tubules as well as lumen diameter, the height of their epithelium and also the number of spermatogonial cells, primary spermatocyte, Sertoli and Leydig cells were compared in the control and experimental groups. At the beginning and on 30[th] and 60[th] days of the experiment, blood samples were taken from the birds for endocrinology investigations and the plasma was separated for measuring the plasma concentration of testosterone and cholesterol. After feeding ostriches with Coenzyme Q10, weight, height, diagonal and testicular gonadosomatic index increased significantly in the experimental groups compared to control group [p

5-HT[1A] receptor activation improves anti-cataleptic effects of levodopa in 6-hydroxydopamine-lesioned rats

In Parkinson_s disease [PD] prolong use of L-DOPA causes some motor disorders such as wearing-off and L-DOPA induced dyskinesia [LID]. In this investigation the effect of 8-OHDAPT, as a 5-HT[1A] agonist on anti-cataleptic effect of L-DOPA in 6-hydroxydopamine [6-OHDA] lesioned male Wistar rats was investigated. Catalepsy was induced by unilateral injection of 6-OHDA [8 micro g/2 micro l/rat] into the central region of the SNc. After 3 weeks as a recovery period, animals received intraperitoneally [i.p.] L-DOPA [15 mg/kg] twice daily for 20 days, and anti-cataleptic effect of L-DOPA was assessed by bar-test at days of 5, 10, 15 and 20. The results showed that L-DOPA had anti-cataleptic effect only until the day of 15, and its effect was decreased on the day of 20. On the day of 21, rats were co-injected with three different doses of 8-OHDAPT [0.1, 0.5 and 2.5 mg/kg, i.p.] and L-DOPA [15 mg/kg, ip]. 8-Hydroxy-2-[di-n-propylamino] tetralin [8-OHDAPT] improved anti-cataleptic effect of L-DOPA at the dose of 0.5 mg/kg. Moreover the effect of 8-OHDAPT on anti-cataleptic effect of L-DOPA [15 mg/kg, ip] was abolished by 1-[2-methyoxyphenyl]-4-[4-[2-phthalamido] butyl] piperazine hydrobromide [NAN-190; 0.5 mg/kg, i.p.] as a 5-HT[1A] receptor antagonist. According to the obtained results, it may be concluded that activation of 5-HT[1A] receptors by 8-OHDAPT may improve anti-cataleptic effect of L-DOPA in a 6-OHDA- induced rat model of PD. Further studies are required to clarify the exact mechanism of interaction between 5-HT[1A] and dopaminergic neurons

[Study of antinociceptive effects of Ziziphora tenuior and its interference on opioidergic and serotoninergic systems]

Ziziphora tenuior has been used in Iranian folk medicine as an analgesic and for treatment of digestive diseases. This study was designed to investigate the antinociceptive effects of hydroalcoholic extract of Z. tenuior on visceral pain and its possible involvement in opioidergic and serotoninergic systems in male albino N-MRI mice. Antinociceptive effect of was determined by writhing test as a model of visceral pain. A. tenuior extract was administered intraperitonealy [ip] in doses of 50, 75 and 100 mg/kg and antinociceptive effects were compared with indomethacin [5mg/kg, i.p.] and control groups. The most effective dose of the extract was selected for the possible involvement of opioidergic and serotoninergic systems. 15 minutes before administration of the effective dose, animals were studied by pretreatment of opioid antagonist, naloxane [2mg/kg, i.p.] and serotoninergic antagonist, cyproheptadine [4mg/ kg, i.p.] using writhing test. The results of this study showed that hydroalcoholic extract of Z. tenuior at 50, 75 and 100 mg/kg and indomethacin [5mg/kg] induced a significant reduction in pain response compared to the control group [p<0.05], while, pretreatment with naloxane and cyproheptadine inhibited some of the extract induced antinociceptive effects in comparison to control group [p<0.05]. This study indicated that some of the antiniciceptive properties of Z. tenuior are mediated by opioidergic and serotonergic mechanisms, which confirmed the traditional uses of the plant in the treatment of pain

role of central endogenous histamine and H[1], H[2] and H[3] receptors on food intake in broiler chickens

The role of endogenous histamine and H[1], H[2] and H[3] central receptors on food intake in broiler chickens was investigated. For this purpose, a probe was used to manipulate the concentration of endogenous histamine by intracerebroventricular [ICV] injection of thioperamide, an H[3] receptor antagonist, and R-alpha-methylhistamine, an H[3] receptor agonist and subsequently the effects of brain histaminergic system on food intake was assessed. Moreover, to determine the receptors involved in histamine-induced feeding behaviour changes, H[1], and H2 blockers were administered to thioperamide-treated chickens. Injection of thioperamide [600 and 300 nmol] decreased food intake dose-dependently [P<0.05]. On the contrary, ICV injection of R-alphamethylhistamine [400 and 200 nmol] increased food intake [P<0.05]. Chlorpheniramine [128 and 256 nmol], a H[1] receptor antagonist, increased food intake [P<0.05]. Famotidine, a H[2] receptor antagonist at 74 or 148 nmol had no effect on food intake but at 296 nmol significantly decreased food intake [P<0.05]. Pretreatment with chlorpheniramine [256 nmol] significantly attenuated thioperamide effects [600 nmol] on food intake [P<0.05]. In conclusion, the results of the present study demonstrated that histamine exerts anorexigenic effects through H[1], but not H[2] receptors in broiler chickens. Furthermore, it was shown that thioperamide through stimulation of synthesis and release of endogenous neuronal histamine can decrease food intake in broiler chickens

[Analgesic effects of extremely low frequency electromagnetic fields in mice]

Environmental factors such as electromagnetic fields influence the pain sensation. To investigate the possible analgesic effect of extremely low frequency electromagnetic fields [ELF-EMFs] exposure and possible interaction between ELF-EMFs and opioid, alpha and beta adrenergic systems. This was an experimental study in which the effect of 60 Hz magnetic field [100mT] on the pain threshold of 80 male albino mice was investigated. Pain threshold was assessed by the tail immersion technique using water with a temperature of 52 C. The mean pain threshold was significantly increased in case group [5.85 +/- 0.69 sec] compared to control group [3.77 +/- 0.55 sec] following ELF-EMF exposure [p<0.0001]. Pretreatment of animals with naloxane [2 mg/kg] and phentolamine [10 mg/kg] significantly reduced the effect to [3.97 +/- 0.7 sec and 4.01 +/- 0.49 sec], respectively [p<0.0001]. There was no change in the value of mean pain threshold [5.77 +/- 0.68 sec] when propranolol [10 mg/kg] was administered [p<0.0001]. Based on our data, exposure to ELF-EMFs could induce analgesic behavior in mice and the associated effect is related to opioid and alpha-adrenergic systems

Body temperature of sheep following intracerebroventricular injections of prostaglandins E[2]and F[2]alpha

The effect of intracerebroventricular injections of prostaglandins E[2] and F[2]alpha was studied on the rectal temperature of sheep. PGE[2] but not PGF[2]alpha at the same dose of 50microg elevated the 1h post-injection of rectal temperature. PGE[2] but not PGF[2] alpha at the same dose of 100microg increased 3.5 and 2h post- injection of rectal temperature, respectively. Elavation of rectal temperature following PGE[2] and PGF[2]alpha injections at the same dose of 200microg lasted to 5 and 3h after injection, respectively. Significant differences between PGE[2] and PGF[2]alpha at the doses of 100 and 200 microg observed from 2[nd] and 3[rd] h after injection. It is concluded that prostaglandins E[2] and F[2]alpha increase the body temperature but the hyperthermic effect of PGE[2] is stronger and longer than that of PGF[2]alpha

[ effect of concurrent injection of amantadine and paroxetine on positive reinforcing effect of morphine in conditioned place preference[CPP] model in mice]

Increased level of dopamine in accumbens nucleus has a key role in the rewarding effects or positive reinforcement of abused drugs, whereas serotonin facilitates dopamine release in brain .The aim of this study was to investigate the effect of concurrent use of amantadine and paroxetine on reinforcing effect of morphine in conditioned place preference model in mice. In this experimental study male NMRI mice [20-30 g] were used within 6 consecutive days including preconditioning, conditioning and postconditioning phases. On the first day, after removal of the partitions, time spent in every 3 compartments was measured for 10 minutes. After determination of low and high preferred side, animals received morphine sulfate [5 mg/kg] intraperitoneally on the 2nd and 4th days in the least preferred side, but on the 3rd and 5th days of the test, animals received saline [10ml/kg] in high preferred side. On the test day or postconditioning phase, animals received amantadine, and paroxetine alone or their concurrent does, instead of morphine. Control group received saline in both sides [n = 8]. Our results show that morphine significantly and dose dependently [2.5, 5,10 mg/kg] induced CPP [P<0.001]. Amantadine, only in doses of 5 and 10 mg /kg [P<0.01, P<0.001, respectively] induced CPP. Paroxetine induced CPP in all doses. Concurrent use of amantadine[10mg/kg] and paroxetine [10mg/kg] significantly enhances morphine - like CPP [P <0.001]. Concurrent use of drugs, releases dopamine and inhibit reuptake of serotonin, and may potentiate morphine-like CPP and could be useful in decreasing some opioid withdrawal signs

Glutamate ionotropic and metabotropic receptors affect feed intake in broiler cockerels

In this study the role of the glutamatergic system on feed intake in 24-hour-feed-deprived broiler cockerels was investigated. ICV injection of 0, 0.675, 1.25, and 2.5 nmol of glutamate reduced feed intake dose-dependently, and increased the latency time to start feeding. Pretreatment with 2.5 nmol HQCA, an ionotropic glutamate antagonist resulted in both an increase in feed intake and a decrease in latency of birds to start feeding. Pretreatment with 2nmol of MSPG, a metabotropic glutamate receptor antagonist, severely reduced feed intake and increased the latency to start feeding. These findings suggest, for the first time, that glutamate, acting as a neurotransmitter, is involved in feed intake regulation in broiler cockerels. This effect is probably mediated by both ionotropic and metabotropic receptors. It appears that both postsynaptic and presynaptic glutamate receptors are involved

[Effect of sexual pheromones, and sexual and paternal behaviors on the plasma level of testosteron in male wistar rat]

Pheromones play a major role in the sexual and social behavior of animals. The main sources of pheromones are urine and paracrine secretions. Pheromones can affect the mammals reproductive physiology. The vomeronasal organ [VNO] is located in the base of nasal cavity and VNO has some effects on amygdal; stimulating the amygdal hence could affectthe mammal's sexual behavior. Through the neuroendocrine system, testosterone is a safe parameter to measure and compare the effects on the sexual behavior. With regard to the neuroendocrine system, testosterone is a safe parameter for measuring the effects of pheromones on sexual behaviors. In this research, we have investigated the of pheromone interaction on sexual behaviors such as intercourse, mating and being near a pregnant female, also paternal behavior after children's birth, have been investigated. The effects of sexual pheromones were determined with a special cage without any sensory stimulation interference, such as visual, auditory, tactile senses [3.58 +/- 0.38 ng/mL]. Proximity between a female and a male rat increased plasma levels of testosterone rapidly [10.59 +/- 2.25 ng/mL, P<0.01]. Mating caused a decrease in testosterone levels comparing to premate groups [4.32 +/- 0.95 ng/mL, P<0.05]. During pregnancy, the testosterone levels increased up to the second week [6.11 +/- 1.58 ng/mL, P<0.017] then decreased rapidly[1.65 +/- 0.37 ng/mL, P<0.017]. After birth of children, the father rat testosterone levels decreased gradually [0.36 +/- 0.14 ng/mL, P<0.017]. But the presence of the father rat's near the strange child rat, the plasma levels of testosterone to increase significantly compared to the increase in mating groups[8.46 +/- 1.26 ng/mL, P<0.017]. These findings suggest that female sexual pheromones and different fatherhood and sexual behaviors, directly affect plasma levels of testosterone and can subsequently affect mating rats' reproductive activities

Light / dark changes of feeding, drinking and defecation in laboratory rabbits

To investigate the 12h: 12h light / dark changesof feeding, drinking and defecation in laboratory rabbits . Experimental study. Ten male New Zealand white rabbits weighing2.5-3kg. Rabbits were individually maintained instandard cages [45 45 60cm] in a laboratory undercontrolled temperature [20 - 23°C] and 12/12h light - darkcycles for induction of adaptation. They were fed with acommercial pelleted diet and water twice daily [7.00 and19.00h]. Fecal pellets and consumed food and water weremeasured every 4h for 10 consecutive days . The rates andratios of the above mentioned parameters were calculatedat 12h light, 12h dark and total 24h periods. Repeated measures ANOVA andDuncan test. Maximal rates of food and water intake wereobtained at 19-23 and 23-3h time intervals. Their minimalrates were occurred at 3-7h time interval. Defecation, withminimal rates at 7-11 and ll-15h time intervals, showedmaximal rates at 15-19, 19-23 and 23-3h time intervals.Food, water intake and defecation rates at 12h dark periodwere higher than that of 12h light period. The 12h dark /total 24h ratios of the parameters were higher than that of12h light / total 24h ratios, too. From the results of this study it isconcluded that laboratory rabbits perform more of feeding,drinking and defecation activities from the beginning tomiddle hours of dark period. From this point of view,rabbits belong to the nocturnal animals group