Cholecystokinin system is involved in the anorexigenic effect of peripherally applied palmitoylated prolactin-releasing peptide in fasted mice.

Prolactin-releasing peptide (PrRP) has been proposed to mediate the central satiating effects of cholecystokinin (CCK) through the vagal CCK1 receptor. PrRP acts as an endogenous ligand of G protein-coupled receptor 10 (GPR10), which is expressed at the highest levels in brain areas related to food intake regulation, e.g., the paraventricular hypothalamic nucleus (PVN) and nucleus of the solitary tract (NTS). The NTS and PVN are also significantly activated after peripheral CCK administration. The aim of this study was to determine whether the endogenous PrRP neuronal system in the brain is involved in the central anorexigenic effect of the peripherally administered CCK agonist JMV236 or the CCK1 antagonist devazepide and whether the CCK system is involved in the central anorexigenic effect of the peripherally applied lipidized PrRP analog palm-PrRP31 in fasted lean mice. The effect of devazepide and JMV236 on the anorexigenic effects of palm-PrRP31 as well as devazepide combined with JMV236 and palm-PrRP31 on food intake and Fos cell activation in the PVN and caudal NTS was examined. Our results suggest that the anorexigenic effect of JMV236 is accompanied by activation of PrRP neurons of the NTS in a CCK1 receptor-dependent manner. Moreover, while the anorexigenic effect of palm-PrRP31 was not affected by JMV236, it was partially attenuated by devazepide in fasted mice. The present findings indicate that the exogenously influenced CCK system may be involved in the central anorexigenic effect of peripherally applied palm-PrRP31, which possibly indicates some interaction between the CCK and PrRP neuronal systems.

Novel lipidized analogs of prolactin-releasing peptide have prolonged half-lives and exert anti-obesity effects after peripheral administration.

OBJECTIVES: Obesity is a frequent metabolic disorder but an effective therapy is still scarce. Anorexigenic neuropeptides produced and acting in the brain have the potential to decrease food intake and ameliorate obesity but are ineffective after peripheral application. We have designed lipidized analogs of prolactin-releasing peptide (PrRP), which is involved in energy balance regulation as demonstrated by obesity phenotypes of both PrRP- and PrRP-receptor-knockout mice. RESULTS: Lipidized PrRP analogs showed binding affinity and signaling in PrRP receptor-expressing cells similar to natural PrRP. Moreover, these analogs showed high binding affinity also to anorexigenic neuropeptide FF-2 receptor. Peripheral administration of myristoylated and palmitoylated PrRP analogs to fasted mice induced strong and long-lasting anorexigenic effects and neuronal activation in the brain areas involved in food intake regulation. Two-week-long subcutaneous administration of palmitoylated PrRP31 and myristoylated PrRP20 lowered food intake, body weight and improved metabolic parameters, and attenuated lipogenesis in mice with diet-induced obesity. CONCLUSIONS: Our data suggest that the lipidization of PrRP enhances stability and mediates its effect in central nervous system. Strong anorexigenic and body-weight-reducing effects make lipidized PrRP an attractive candidate for anti-obesity treatment.

Effect of ghrelin receptor agonist and antagonist on the activity of arcuate nucleus tyrosine hydroxylase containing neurons in C57BL/6 male mice exposed to normal or high fat diet.

Catecholamines participate in the food intake regulation, however, there are no literature data available, dealing with the activity of tyrosine hydroxylase (TH) neurons in response to stimulation or inhibition of GHS-R (growth hormone secretagogue receptor) in the hypothalamic arcuate nucleus (ARC). The present study was focused to reveal whether [Dpr(N-octanoyl) 3ghrelin], a stable GHS-R agonist, itself in doses of 5 or 10 mg/kg (s.c.) or in combination with GHS-R receptor antagonist ([DLys3]GHRP-6) in dose of 10 mg/kg (s.c.), may affect the activity of ARC TH-containing neurons in C57BL/6 male mice fed either with standard (SD) or high fat diet (HFD) that developed a diet-induced obesity (DIO). The data of the present study clearly indicate that both doses of GHS-R agonist stimulated food intake in SD mice and GHS-R antagonist significantly reduced GHS-R agonist orexinergic effect in SD mice and suppressed the voluntary food intake in HFD mice. Both doses of the GHS-R agonist stimulated Fos expression in ARC neurons in both diet groups of mice which was not abolished by GHS-R antagonist pretreatment. Moreover, both doses of the GHS-R agonist significantly influenced the activation of TH neurons in the ARC of SD mice. The GHS-R antagonist also significantly increased TH neurons activation after GHS-R agonist although this effect was less powerful in HFD mice. This is the first study demonstrating response of local ARC TH neurons to peripherally applied GHS-R agonist and antagonist. The present data point out that the response of TH neurons to GHS-R agonist and antagonist is different in normal and DIO mice and extend our knowledge about the further ARC neuronal phenotype responding to peripheral ghrelin. To bring insight into the understanding of the functional significance of the activated TH neurons in ARC, in the context of the ghrelin peripheral increase, further studies are required.

High fat diet impact on Fos expression in ovariectomized female C57BL/6 mice: effect of colchicine and response of different neuronal phenotypes.

OBJECTIVES: Activity of neuropeptide Y (NPY), tyrosine hydroxylase (TH), corticoliberine (CRH), and oxytocin (OXY) producing cells was investigated in the ovariectomized (OVX) female C57BL/6 mice kept on the high fat diet for 16 weeks and their response to colchicine stress in selected brain areas, including the hypothalamic paraventricular (PVN), dorsomedial (DMN) and arcuate (ARC) nuclei, A1/C1 (in the ventrolateral medulla), and A2/C2 (in the nucleus of the solitarii tract, NTS) catecholaminergic cell groups. METHODS: The OVX female C57BL/6 mice kept on high fat diet were sacrificed by transcardial perfusion with fixative 48 h after intracerebroventricular injection of colchicine (18 µg mice). Dual Fos/neuropeptide immunohistochemistry was employed to investigate Fos/neuropeptide colocalizations. RESULTS: In the OVX saline-treated mice (sham control) with standard diet (St diet), no immunopositive CRH and NPY neurons were identified in the PVN and weak Fos immunostainig was visible in TH neurons in the DMN and ARC nuclei. Colchicine treatment in the OVX mice with St diet increased the number of CRH and OXY immunopositive neurons in the PVN as well as the number of NPY and TH neurons in DMN and ARC nuclei and NPY neurons in the middle NTS (mNTS) and A1/C1 cell group. Prolonged HF diet in OVX sham control mice moderately increased the number of Fos/TH neurons in the mNTS and commissural NTS (cNTS) in comparison with St diet mice. However, prolonged HF diet in OVX colchicines-treated mice reduced the number of Fos/NPY neurons in the anterior NTS (aNTS) and A1/C1 cell group in comparison with colchicines-treated animals with St diet as well as Fos-TH neurons in the mNTS and cNTS in comparison with saline-treated animals with HF diet. CONCLUSION: The data of this pilot study indicate that prolonged high fat diet might: 1) represent itself a light/moderate stimulus for activation of TH neurons in the NTS and A1/C1 cell group as well as NPY neurons in the A1/C1 cell group and 2) interfere with colchicines-induced and time-delayed Fos activation in the NPY and TH neurons in both the above mentioned brain nuclei.

Ghrelin agonists impact on Fos protein expression in brain areas related to food intake regulation in male C57BL/6 mice.

Many peripheral substances, including ghrelin, induce neuronal activation in the brain. In the present study, we compared the effect of subcutaneously administered ghrelin and its three stable agonists: Dpr(3)ghr ([Dpr(N-octanoyl)(3)] ghrelin) (Dpr - diaminopropionic acid), YA GHRP-6 (H-Tyr-Ala-His-DTrp-Ala-Trp-DPhe-Lys-NH(2)), and JMV1843 (H-Aib-DTrp-D-gTrp-CHO) on the Fos expression in food intake-responsive brain areas such as the hypothalamic paraventricular (PVN) and arcuate (ARC) nuclei, the nucleus of the solitary tract (NTS), and area postrema (AP) in male C57BL/6 mice. Immunohistochemical analysis showed that acute subcutaneous dose of each substance (5mg/kg b.w.), which induced a significant food intake increase, elevated Fos protein expression in all brain areas studied. Likewise ghrelin, each agonist tested induced distinct Fos expression overall the PVN. In the ARC, ghrelin and its agonists specifically activated similarly distributed neurons. Fos occurrence extended from the anterior (aARC) to middle (mARC) ARC region. In the latter part of the ARC, the Fos profiles were localized bilaterally, especially in the ventromedial portions of the nucleus. In the NTS, all substances tested also significantly increased the number of Fos profiles in neurons, which also revealed specific location, i.e., in the NTS dorsomedial subnucleus (dmNTS) and the area subpostrema (AsP). In addition, cells located nearby the NTS, in the AP, also revealed a significant increase in number of Fos-activated cells. These results demonstrate for the first time that ghrelin agonists, regardless of their different chemical nature, have a significant and similar activating impact on specific groups of neurons that can be a part of the circuits involved in the food intake regulation. Therefore there is a real potency for ghrelin agonists to treat cachexia and food intake disorders. Thus, likewise JMV1843, the other ghrelin agonists represent substances that might be involved in trials for clinical purposes.

Brain-liver interactions during liver ischemia reperfusion injury: a minireview.

KEYWORDS: The liver is a vital organ, with a wide range of functions. This organ plays an important role in the metabolism, including the glycogen storage, decomposition of red blood cells, plasma protein synthesis, hormone production, and detoxification. The liver is innervated by sympathetic and parasympathetic nerves which are involved in the regulation of the hepatic metabolism. Tissue injury connected with ischemia and reperfusion has been implicated in several clinical settings, including myocardial infarction, brain ischemia, and organ transplantation. Consequences of the liver ischemia reperfusion injury (LIRI) induce first of all an organ failure and afterwards multiorgan system damages that may eventually lead to a death. Many models with an attempt to reduce harmful consequences of the LIRI, directing to develop a variety of prophylactic strategies, has been introduced including models of warm, cold or normothermic ischemia, ischemic pre- and post-conditionings, pharmacological interventions, etc. In spite of the improvements in the medical care and accumulation of a large amount of experimental data concerning the prevention of ischemia and reperfusion related injuries, many destructive processes explanation still remains problematic.

Activation of different neuronal phenotypes in the rat brain induced by liver ischemia­reperfusion injury: dual Fos/neuropeptide immunohistochemistry.

The aim of the present study was to reveal the effect of liver ischemia­reperfusion injury (LIRI) on the activity of selected neuronal phenotypes in rat brain by applying dual Fos-oxytocin (OXY), vasopressin (AVP), tyrosine hydroxylase (TH), phenylethanolamine N-methyltransferase (PNMT), corticoliberine (CRH), and neuropeptide Y (NPY) immunohistochemistry. Two liver ischemia­reperfusion models were investigated: (i) single ligation of the hepatic artery (LIRIa) for 30 min and (ii) combined ligation of the portal triad (the common hepatic artery, portal vein, and common bile duct) (LIRIb) for 15 min. The animals were killed 90 min, 5 h, and 24 h after reperfusion. Intact and sham operated rats served as controls. As indicated by semiquantitative estimation, increases in the number of Fos-positive cells mainly occurred 90 min after both liver reperfusion injuries, including activation of AVP and OXY perikarya in the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei, and TH, NPY, and PNMT perikarya in the catecholaminergic ventrolateral medullar A1/C1 area. Moreover, only PNMT perikarya located in the A1/C1 cell group exhibited increased Fos expression 5 h after LIRIb reperfusion. No or very low Fos expression was found 24 h after reperfusion in neuronal phenotypes studied. Our results show that both models of the LIRI activate, almost by the same effectiveness, a number of different neuronal phenotypes which stimulation may be associated with a complex of physiological responses induced by (1) surgery (NPY, TH, PNMT), (2) hemodynamic changes (AVP, OXY, TH, PNMT), (3) inflammation evoked by ischemia and subsequent reperfusion (TH), and (4) glucoprivation induced by fasting (NPY, PNMT, TH). All these events may contribute by different strength to the development of pathological alterations occurring during the liver ischemia­reperfusion injury.

The α2-adrenoceptors do not modify the activity of tyrosine hydroxylase, corticoliberine, and neuropeptide Y producing hypothalamic magnocellular neurons ion the Long Evans and Brattleboro rats.

The hypothalamic supraoptic (SON) and paraventricular (PVN) nuclei are activated by body salt-fluid variations. Stimulation of alpha(2)-adrenoceptors by an agonist-xylazine (XYL) activates oxytocinergic but not vasopressinergic magnocellular neurons. In this study, tyrosine hydroxylase (TH), corticoliberine (CRH), and neuropeptide Y(NPY) magnocellular phenotypes, were analysed in response to alpha(2)-adrenoceptor manipulations and sustained hyperosmolality in vasopressin deficient homozygous Brattleboro (di/di) rats. Saline (0.9% NaCl, 0.1 ml/100g/bw), XYL (10 mg/kg/bw), atipamezole (ATIP, alpha(2)-adrenoceptors antagonist, 1 mg/kg/bw), and ATIP 5 min later followed by XYL, were applied intraperitoneally. Presence of immunolabeled Fos peptide signalized the neuronal activity. Ninety minutes after injections, the rats were anesthesized and sacrificed by transcardial perfusion with fixative. Coronal sections of 30 mum thickness double immunolabeled with Fos/neuropeptide were evaluated under light microscope. Under basal conditions, di/di in comparison with control Long Evans rats, displayed significantly higher number of TH, CRH, and NPY immunoreactive neurons in the SON and PVN (except NPY cells in PVN) and more than 90%, 75%, and 86% of TH, NPY, and CRH neurons, respectively, displayed also Fos signal in the SON. XYL did not further increase the number of Fos in the PVN and SON and ATIP failed to reduce the stimulatory effect of hypertonic saline in all neuronal phenotypes studied. Our data indicate that hyperosmotic conditions significantly influence the activity of TH, CRH, and NPY magnocellular neuronal phenotypes, but alpha(2)-adrenoceptors do not play substantial role in their regulation during osmotic challenge induced by AVP deficiency.

Fos expression in tyrosine hydroxylase containing hypothalamic neurons in CRH-KO mice: effect of immobilization stress.

OBJECTIVE: Little is known about the response of tyrosine hydroxylase (TH) containing hypothalamic neurons to stress in corticoliberine deficient (CRH-KO) mice. This study was aimed to extend this issue and reveal the data leading to a better understanding of physiological/anatomical plasticity of hypothalamic TH cells in response to acute immobilization stress (IMO) as well as of possible of CRH body deficiency contribution in the regulation of TH cells during stress. We examined the topographic distribution of TH protein immunolabeled perikarya in selected hypothalamic structures including the paraventricular (PVN), supraoptic (SON), periventricular (PeVN), arcuate (ArcN), dorsomedial (DMN), and ventromedial (VMN) nuclei and extrahypothalamic zona incerta (ZI) in CRH-KO and wild type (WT) mice. METHODS: The animals were perfused with fixative 120 min after a single IMO stress. The brains were removed, cryo-sectioned throughout the hypothalamus and Fos-TH co-localizations were processed immunohistochemically. Fos protein was visualized by diaminobenzidine (DAB) intensified with nickel ammonium sulphate, while TH cells were labeled only with DAB chromogen. The evaluation of Fos-TH co-labeled perikarya was performed with the use of computerized Leica light microscope and expressed as the percentage of total amount of TH labeled cells. RESULTS: From the qualitative point of view, the present data indicate similar anatomical distribution of TH immunoreactive perikarya in all brain structures investigated in both WT and CRH-KO mice, while from the quantitative point of view only TH cells in the DMN of CRH-KO mice showed a trend for increased activation by IMO. CONCLUSIONS: In several hypothalamic structures the basic population of TH neurons was not affected by the absence of endogenous CRH. Based on the data of this study it can also be assumed that despite of the presence of direct reciprocal connections between PVN and DMN neurons, PVN CRH neurons possibly are not participating in the regulation of TH neurons in the DMN during IMO stress. KEYWORDS: Hypothalamic nuclei - Fos-immunohistochemistry - Tyrosine hydroxylase - Immobilization stress - CRH knockout mice.

Different antipsychotics elicit different effects on magnocellular oxytocinergic and vasopressinergic neurons as revealed by Fos immunohistochemistry.

Acute administration of antipsychotics elicits regionally distinct patterns of Fos expression in the rat brain. Stimulation of oxytocin (OXY) and vasopressin (AVP) release in the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei indicates that antipsychotics may play a role in autonomic, neuroendocrine, and behavioral processes. This study was focused to reveal the responsiveness of hypothalamic OXY- and AVP- producing magnocellular neurons, in terms of quantitative and topographical distinctions, to antipsychotics displaying different pharmacological profiles. Naive male Wistar rats were injected intraperitoneally with haloperidol (1 mg/kg), clozapine (30 mg/kg), olanzapine (30 mg/kg), risperidone (2mg/kg), and vehicle (5% chremophor) and were sacrificed 60 min later by a fixative. Fos, Fos/OXY, and Fos/AVP labelings were visualized by immunohistochemistry in the SON, 5 accessory (ACS) cell groups, and 4 distinct PVN subdivisions using a computerized light microscope. Most apparent activation of single Fos, Fos/OXY, and Fos/AVP cells was induced by clozapine and olanzapine; effects of risperidone and haloperidol were substantially lower; no colocalizations were revealed in naive or vehicle treated control rats. The data indicate the existence of a substantial diversity in the stimulatory effect of the selected antipsychotics on quantity of Fos, Fos/OXY, and Fos/AVP immunostainings with the preferential action of the atypicals clozapine over olanzapine and little effects of risperidone and haloperidol. Variabilities in Fos distribution in the PVN, SON, and ACS induced by antipsychotics may be helpful to understand more precisely the extent of their extra-forebrain actions with possible presumption of their functional impact and side effect consequences.

Response of hypothalamic oxytocinergic neurons to immobilization stress is not dependent on the presence of corticotrophin releasing hormone (CRH): a CRH knock-out mouse study.

This study explores the quantitative patterns of immunolabeled Fos protein incidence in the hypothalamic paraventricular (PVN) and supraoptic nuclei (SON) oxytocinergic (OXY) neurons in response to immobilization (IMO) stress in corticotrophin releasing hormone deficient (CRH-KO) mice. Adult male mice, taken directly from cages or 120 min after a single IMO, were sacrificed by intracardial perfusion with fixative. Coronal brain sections of 30 mum thickness were processed for dual Fos/OXY immunohistochemistry. In control wild type (WT) and CRH-KO mice, scattered Fos immunoreactivity was observed in hypothalamus, including the PVN where scanty Fos signal occurred in both parvocellular and magnocellular PVN subdivisions. Dual Fos/OXY immunostainings revealed higher basal Fos expression in the PVN of control CRH-KO mice. IMO evoked a marked rise in Fos expression in OXY neurons of the PVN and SON in both WT and CRH-KO groups of mice. The present data demonstrate that 1/ CRH deficiency upregulates the basal activity of hypothalamic PVN OXY cells in CRH-KO mice and 2/ IMO stress in both WT and CRH-KO mice affects distinctly the activity of OXY cells in both SON and PVN. Our data indicate that CRH deficiency does not alter the responsiveness of PVN and SON OXY cells to IMO stress.

Comparison of the obesity phenotypes related to monosodium glutamate effect on arcuate nucleus and/or the high fat diet feeding in C57BL/6 and NMRI mice.

In this study, susceptibility of inbred C57BL/6 and outbred NMRI mice to monosodium glutamate (MSG) obesity or diet-induced obesity (DIO) was compared in terms of food intake, body weight, adiposity as well as leptin, insulin and glucose levels. MSG obesity is an early-onset obesity resulting from MSG-induced lesions in arcuate nucleus to neonatal mice. Both male and female C57BL/6 and NMRI mice with MSG obesity did not differ in body weight from their lean controls, but had dramatically increased fat to body weight ratio. All MSG obese mice developed severe hyperleptinemia, more remarkable in females, but only NMRI male mice showed massive hyperinsulinemia and an extremely high HOMA index that pointed to development of insulin resistance. Diet-induced obesity is a late-onset obesity; it developed during 16-week-long feeding with high-fat diet containing 60 % calories as fat. Inbred C57BL/6 mice, which are frequently used in DIO studies, both male and female, had significantly increased fat to body weight ratio and leptin and glucose levels compared with their appropriate lean controls, but only female C57BL/6 mice had also significantly elevated body weight and insulin level. NMRI mice were less prone to DIO than C57BL/6 ones and did not show significant changes in metabolic parameters after feeding with high-fat diet.

Effect of pentoxifylline on endothelaemia and hypothalamic-pituitary-adrenocortical axis activation in female rats under stress exposure.

Endothelial dysfunction may belong to negative consequences of stress exposure accompanied by activation of several stress systems including the hypothalamic-pituitary-adrenocortical (HPA) axis. The present experiments were aimed at testing the hypotheses that i) immobilization (IMO) stress results in sustained increase in endothelaemia for 24 h and that ii) pentoxifylline, a drug with endothelium protective properties, attenuates the rise in endothelaemia and HPA axis activation in female rats as shown previously in males. Circulating endothelial cells increased immediately after the IMO for 2 h, returned back to control levels at 12 h and increased again at 24 h. Stress-induced rise in adrenocorticotropic hormone (ACTH) and corticosterone levels was particularly high immediately after the IMO. Pretreatment with pentoxifylline (20 mg/kg subcutaneously for 7 days) attenuated the rise in endothelaemia and adrenal corticosterone measured at 24 h following IMO. Plasma levels of ACTH and proopiomelanocortin gene expression in the anterior pituitary were not affected by pentoxifylline treatment. The present results indicate that IMO stress in female rats induces a biphasic rise in endothelaemia early at the time of stress exposure and than 24 h thereafter. Based on these data and our previous study we can conclude that intensive stress has a negative influence on endothelial cells in both sexes and no gender differences seem to be present in the protective action of pentoxifylline.

Xylazine activates oxytocinergic but not vasopressinergic hypothalamic neurons under normal and hyperosmotic conditions in rats.

Role of central alpha2-adrenoceptors in the regulation of hypothalamic magnocellular cells was studied under hyperosmotic challenge elicited by hypertonic saline (HS). Rats pretreated with receptor agonist, xylazine (XYL), were injected intraperitoneally with different (low: 0.375, moderate: 0.75, high: 1.5 M) HS 30 min later. The activity of the paraventricular (PVN) and supraoptic (SON) vasopressin and oxytocin perikarya was established by Fos-dual-immunohistochemistry 60 min after HS administration. Results showed that 1/XYL is a potent stimulus for oxytocin but not vasopressin magnocellular cells under basal and weak hyperosmotic conditions 2/highHS completely overlaps the effect of XYL. In addition, XYL partially suppressed Fos expression in the parvocellular PVN cells activated by highHS. The data suggest that alpha2-adrenoceptors may play an important role in the regulation of oxytocinergic PVN and SON neurons under basal and weak hyperosmotic conditions and that alpha2-adrenoceptors may also participate in the control of PVN parvocellular cells under intense osmotic challenge.

Fos protein expression in mouse hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei upon osmotic stimulus: colocalization with vasopressin, oxytocin, and tyrosine hydroxylase.

The quantity and topography of activated vasopressin (AVP), oxytocin (OXY), and tyrosine hydroxylase (TH) neurons were studied immunohistochemically in the anterior, middle, and posterior portions of the PVN and SON in mice 60 min after a single injection of hypertonic saline (HS, 400 microl 1.5M, i.p.). Fos-neuropeptide double-stainings revealed: (1) Fos expression in each portion of the PVN and SON; (2) maximal number of Fos-AVP (79 cells) and Fos-OXY (50 cells) double-labelings in the middle portion of the PVN; (3) low number of Fos-TH perikarya in the PVN and their lack in the SON; (4) similar incidence (around 50%) of Fos-AVP and Fos-OXY perikarya in the SON; and (5) presence of activated AVP, OXY, and TH neurons in the periventricular, subependymal, and sub-PVN zones of the PVN. Topographic analysis revealed that the majority of AVP neurons expressing Fos occupied the dorsolateral and central part of the middle portion of the PVN. In the same PVN portion, Fos-OXY neurons occurred in similar frequency, however, they were primarily distributed along the lateral and medial margins of the PVN. In the SON, Fos-OXY cells occupied mainly its dorsal, while Fos-AVP cells predominated in its ventral part. The data clearly indicate that HS is not a selective stimulus neither for PVN nor SON itself and provide evidence that both PVN and SON AVP and OXY cells play important role in the mediation of signals induced by HS. In addition, the limited number of AVP, OXY, and TH neurons activated by HS may account for their differential functional specializations selective for stress/osmotic circuits activated by HS.

Stress-induced rise in endothelaemia, von Willebrand factor and hypothalamic-pituitary-adrenocortical axis activation is reduced by pretreatment with pentoxifylline.

Stress is considered to be a risk factor of several diseases. The following hypotheses were tested: (1) single exposure to an intensive stressor is followed by endothelial stimulation and/or damage to endothelial cells, (2) potential stress-induced endothelial cell damage is reduced by repeated pretreatment with pentoxifylline and (3) pentoxifylline treatment modifies neuroendocrine activation during stress reflected by changes in hypothalamic-pituitary-adrenocortical (HPA) axis function. Rats were treated with saline or pentoxifylline (20 mg/kg, s.c.) once daily for 7 days and then exposed to single immobilization stress for 20 or 120 min. In saline pretreated rats, stress exposure was followed by a rise in endothelaemia, von Willebrand factor concentrations, adrenocorticotropic hormone (ACTH) and corticosterone release, as well as by enhanced gene expression of hypothalamic corticotropin releasing factor (CRH). Stress-induced changes were reduced by pretreatment with pentoxifylline. Significant inhibition was observed in endothelaemia, plasma ACTH and corticosterone concentration in the adrenals. Thus, signs of endothelial injury as well as stress-induced hormone levels were reduced by pretreatment with pentoxifylline, although there is no evidence for a causal relationship. This protective action of pentoxifylline might be of benefit in the prevention and therapy of some stress-related disorders.

[The cerebellum: anatomy, distribution of mediators and their receptors, communication with hypothalamic structures and comparison with the hypothalamic paraventricular nucleus under conditions of stress]. / Cerebelum: strucná anatómia, distribúcia mediátorov a ich receptorov, komunikovanie so struktúrami hypotalamu a porovnanie s paraventrikulárnym jadrom hypotalamu v podmienkach stresu.

Cerebellum is a profound structure of the central nervous system. Human cerebellum weighs about 150 g which represents around 10% of the total weight of the brain. It receives main input from sensory systems but the cerebellum functions as a part of the motor system. The cerebellum contributes by only few direct connections to motoneurons (therefore it cannot initiate any motor activity) but it projects profusely to all major motor control regions of the cerebral cortex. The cerebellum acts as a controller and coordinator. It compares movement intention with, performance and coordinates the equilibrium, posture and muscle tone necessary for the smooth coordinated motor activity. The number of input projections which exceed considerably the output ones (40:1) speaks out of an enormous analytical and synthetic capacity of the cerebellum. Interneuronal transmission of informations and carriage of afferent and efferent signals are provided by wide variety of chemical messengers (amino acids, biogenic amines and neuropeptides) of the local origin or delivered from the precerebellar nuclei. Direct and reciprocal connections between the hypothalamus and cerebellum have anatomically been well documented but monosynaptic contacts between the cerebellum and the hypothalamic paraventricular nucleus have not been approved yet. Cerebellum can respond to stress, however, this response may not be related only to the primary effect of the stressor but also to its consequences.

Single dose of morphine influences plasma corticosterone and gene expression of main NMDA receptor subunit in the adrenal gland but not in the hippocampus.

OBJECTIVE: This study was aimed to evaluate the effects of morphine on hypothalamo-pituitary-adrenocortical (HPA) axis, namely proopiomelanocortin (POMC) mRNA and plasma corticosterone, in relation to its influence on glutamate receptor gene expression in central and peripheral sites related to HPA axis regulation. As previous data on morphine action were obtained mainly in male rats, these experiments were performed in females to see potential gender differences. METHODS: Adult female Sprague-Dawley rats were injected with a single dose of morphine (10 mg/kg s.c.) or vehicle. Blood and tissues were sampled 4 h and 24 h following the treatment. In situ hybridization was used to measure POMC mRNA concentrations, reverse transcription-polymerase chain reaction to quantify mRNA coding for N-methyl-D-aspartic acid (NMDA) receptor subunit 1 and radioimmunoassay to measure plasma corticosterone. RESULTS: Single dose of morphine was followed by a decrease in gene expression of glutamate receptor subunit NMDAR1 in the adrenal gland. Concentrations of mRNAs coding for NMDAR1 in the hippocampus and for POMC in the anterior pituitary remained unaffected. However, plasma corticosterone levels, which were measured at 4 and 24 h after the treatment with morphine, showed a disturbed daily variation in corticosterone release. The efficacy of morphine was confirmed by Straub tail response, one of the classical effects of this drug, in mice. CONCLUSIONS: Present data obtained in females allow to suggest that morphine exerts some of its effects on HPA axis by POMC unrelated mechanisms seemingly in a gender specific manner. Decrease in glutamate receptor gene expression in adrenals induced by a single dose of morphine may result in a modulation of adrenal function in response to subsequent exposure to opioids and contribute to some alterations occurring during opioid drug abuse.