Biomedical subjects

Krystyna Skwarlo-Sonta

Publications and source records attributed to Krystyna Skwarlo-Sonta.

9 recordsLinked to original sources

PubMed2006

PACAP 38 as a modulator of immune and endocrine responses during LPS-induced acute inflammation in rats.

The effect of PACAP 38 administration on neuroendocrine and immune parameters was examined in rats with LPS-induced peritonitis. Treatment with PACAP 38 alone did not influence the serum level of the cytokines and hormones examined, but significantly decreased immune cell activity. When administered together with LPS, PACAP 38 reversed its effect on immune and humoral parameters, causing a decrease in the serum concentrations of TNFalpha and corticosterone, and an increase in T4 and GH. The majority of PACAP 38 effects disappeared earlier than those previously observed for VIP. PACAP 38 appears to represent a short-lasting modulator of immune and endocrine responses during acute inflammation.

Acute Disease↗

PubMed2005

Anti-inflammatory and opioid-mediated effects of melatonin on experimental peritonitis in chickens.

The immunomodulatory properties of melatonin (Mel) are generally recognized but the mechanisms of its action are not fully understood. In mammals, some of the immunomodulatory effects of Mel are mediated by opioids synthesized by immune cells under its influence. The present study was performed to examine whether Mel-induced opioids are involved in the immunomodulatory activity of Mel in chickens. Experimental peritonitis was evoked by a single ip injection of thioglycollate (TG), and half of the birds were pre-treated with Mel. Some of the Mel-treated birds were additionally pre-treated with naltrexone, an antagonist of opioid receptors. Control birds received an injection of saline, Mel or were untreated. At specific post-injection intervals chickens were sacrificed, the peritoneal cavity was flushed out and peritoneal leukocytes (PTLs) were counted. The activity of PTLs was measured in vitro by the level of reactive oxygen species (ROS). Splenocytes were isolated aseptically and mitogen-stimulated in vitro proliferation was assessed. In PTLs and splenocytes the expression of opioid (proopiomelanocortin and proenkephalin) genes was also examined. Mel exerted a bi-phasic effect on TG-induced peritonitis in chickens: initially it blocked the development of peritonitis, decreasing the number of PTLs and intracellular ROS level (anti-inflammatory action), and thereafter an increase in both PTL number and ROS level was observed (pro-inflammatory action). The pro-inflammatory effect occurred a few hours after the induction of expression of the proenkephalin gene in PTLs and both the proenkephalin and proopiomelanocortin genes in splenocytes. These effects were prevented by naltrexone, suggesting involvement of the opiatergic mechanism.

Adjuvants, Immunologic↗

PubMed2005

Effect of melatonin on phagocytic activity and intracellular free calcium concentration in testicular macrophages from normal and streptozotocin-induced diabetic rats.

This study examined the effect of melatonin (MLT) on in vitro phagocytosis of testicular macrophages taken from control and streptozotocin (STZ)-induced diabetic rats and the possible mechanism of its action. The phagocytic activity was measured as a number of latex beads ingested by 100 macrophages (PI, phagocytic index) in consecutive time points of the incubation. Changes in intracellular free calcium level [Ca2+]i in isolated macrophages in vitro were measured with the use of ratio-image fluorescence microscopy (fluorescent dye: Fura2/AM). Phagocytic index in macrophages isolated from healthy rats was 20% higher than in those from diabetic animals. Melatonin in physiological concentration (10(-7) M) significantly (p < 0.05) increased the PI in testicular macrophages from control animals (PI = 68 +/- 5 with MLT compared to PI = 46 +/- 7 without MLT) while no such effect was observed in the cells from diabetic rats (PI = 36 +/- 23 with MLT compared to PI = 31 +/- 11 without MLT). Basal [Ca2+]i was significantly (p < 0.01) higher in macrophages from diabetic rats compared to control. Stimulation of both control and diabetic testicular macrophages with 10(-7) M MLT resulted in a significant (p < 0.05) increase in [Ca2+]i in cells incubated in 2.5 mM calcium solution while no such response was observed in calcium-free Tyrode solution. However, MLT evoked [Ca2+]i response in macrophages isolated from diabetic animals was much lower than in macrophages isolated from age-matched controls and the time needed for maximal response was much longer. Lack of response in calcium-free solution suggests that extracellular calcium may be necessary to trigger MLT response and in its progression.

Analysis of Variance↗

PubMed2003

Bidirectional communication between the pineal gland and the immune system.

The pineal gland is a vertebrate neuroendocrine organ converting environmental photoperiodic information into a biochemical message (melatonin) that subsequently regulates the activity of numerous target tissues after its release into the bloodstream. A phylogenetically conserved feature is increased melatonin synthesis during darkness, even though there are differences between mammals and birds in the regulation of rhythmic pinealocyte function. Membrane-bound melatonin receptors are found in many peripheral organs, including lymphoid glands and immune cells, from which melatonin receptor genes have been characterized and cloned. The expression of melatonin receptor genes within the immune system shows species and organ specificity. The pineal gland, via the rhythmical synthesis and release of melatonin, influences the development and function of the immune system, although the postreceptor signal transduction system is poorly understood. Circulating messages produced by activated immune cells are reciprocally perceived by the pineal gland and provide feedback for the regulation of pineal function. The pineal gland and the immune system are, therefore, reciprocally linked by bidirectional communication.

Animals↗

PubMed2002

Effect of morphine on thioglycollate-induced peritonitis in chickens.

BACKGROUND: Morphine exerts immunomodulatory effects dependent on several factors including species and parameter examined. The aim of this study was to assess the influence of morphine on experimental peritonitis and leukocyte activity in young chickens of both sexes. METHODS: Peritonitis was elicited by intraperitoneal injection of thioglycollate (TG) alone or supplemented with morphine; additional chicken groups were injected with morphine alone. Morphine-treated birds (with or without elicited peritonitis) were pretreated with naltrexone, an antagonist of opioid receptors. Control groups were intact or PBS-injected. At specific postinjection intervals peritoneal leukocytes (PTL) were obtained by flushing the peritoneal cavity, counted and used for in vitro assays of activity (respiratory burst). Vascular permeability was measured using Evans blue solution. RESULTS: Inflammatory reaction and morphine influence were gender-dependent: the extent of TG-induced peritonitis was higher in males and it was additionally stimulated by morphine. This pro-inflammatory effect of morphine was not seen in females. PTL collected from morphine-treated chickens of both sexes exhibited a stronger nitroblue tetrazolium reduction than in non-treated birds and this effect was antagonized by naltrexone. CONCLUSIONS: The effect of morphine on peritonitis in chickens appears different to that in other vertebrate species, although the mechanism(s) of its influence on leukocyte activity are similar.

Analgesics, Opioid↗

PubMed2002

Melatonin in immunity: comparative aspects.

Pineal gland, by the diurnal rhythm of synthesis and release of its principal hormone, melatonin (MEL), is involved in reciprocal relationships between neuroendocrine and immune systems, responsible for keeping internal homeostasis in vertebrate animals. In this paper the experimental data, indicating that both strategic (developmental, thus antigen independent) and emergency (evoked by antigenic activation of the mature immune system) levels of interactions between pineal gland and immune system, operate in mammals and birds, are reviewed. The cells and organs of immune system using membrane receptors as well as nuclear orphan receptors perceive MEL message. Effects exerted by MEL on immune parameters are different, and depend on several factors, including dose and way of MEL application, species, sex, age of animal, its immune system maturation, way of immune system activation, and parameter examined, as well as the season, circadian rhythm of both immunity and pineal gland function, stressful conditions, accompanying experimental procedure, etc. In turn, lymphoid organ-derived hormones and cytokines, soluble factors secreted by activated immune cells act as messages understood by the pineal gland, closing the regulatory loop of the bi-directional functional connections between both systems.

Animals↗

PubMed2002

Influence of melatonin on chicken lymphocytes in vitro: involvement of membrane receptors.

OBJECTIVES: Time-dependent melatonin effects on chicken lymphocyte proliferation in vitro and the involvement of cAMP in melatonin signal transduction were examined. MATERIALS AND METHODS: Splenocytes and peripheral blood mononuclear cells (PBMC) were cultured in vitro in the presence of melatonin, phytohemagglutinin, luzindole, dibutyrylcAMP (dbcAMP), forskolin and vasoactive intestine peptide (VIP). Proliferation was measured by [(3)H]-thymidine incorporation in cultures carried out for 24, 36, 48 and 72 h. Cyclic AMP formation was assessed by radioimmunoassay in cells incubated for 30 min. or 24 h. RESULTS: Melatonin stimulated the spontaneous proliferation in short-term (36 and 48 h) splenocyte cultures and had no effect in 72 h cultures. It inhibited mitogen-stimulated proliferation already in 24 h cultures and this effect was observed regardless of the time of the culture. Both melatonin effects were antagonized by luzindole - membrane-bound melatonin receptor antagonist. Forskolin and dbcAMP caused a significant inhibition of proliferation of splenocytes and PBMC cultured for 24 or 72 h, respectively. Melatonin inhibited the cAMP formation (30 min. of incubation) stimulated by adenosine cyclase activators - forskolin and VIP, but added alone failed to affect the cAMP concentration. In mitogen-stimulated splenocytes cultured for 24 h Mel caused an increase in cAMP correlated with the inhibition of cell proliferation. CONCLUSIONS: Melatonin effects on chicken splenocytes appears time- and activation-dependent: in short-term cultures it stimulates spontaneous and inhibits mitogen-activated proliferation, probably via membrane-bound, luzindole-sensitive melatonin receptors. Incubation with melatonin for 30 min. inhibits cAMP formation, but in 24 h cultures it increases cAMP concentration leading to inhibition of proliferation.

Animals↗

PubMed2000

Effect of immunization on nocturnal NAT activity in chicken pineal gland.

OBJECTIVES: The effect of a single immunization with sheep red blood cells (SRBC) on the nocturnal NAT activity in the pineal gland and serum anti-SRBC agglutinin titer was examined in the young, sexually immature ASTRA S chickens. METHODS: 3-, 4-, and 5-week-old birds of both sexes, hatched in long (Spring) and short (Autumn) day, were housed from hatching in controlled light (L:D = 12:12) and temperature conditions. Quantity of produced 14C-labeled N-acetyltryptamine was used as a measure of the nocturnal NAT activity in the pineal gland. Serum anti-SRBC agglutinins were determined by microhemagglutination test. RESULTS: In experimental conditions applied, a sexual dimorphism in both pineal gland function and immune system activity was observed. NAT activity was dependent on the season, sex and age of chickens examined and was modified by the single immunization with SRBC. CONCLUSION: Results obtained confirmed once again the existence of the reciprocal functional connection between the pineal gland and immune system in chickens and demonstrated that even in well controlled experimental conditions the influence of the seasonal factor(s) on immunity must be taken into consideration.

Journal Article↗

PubMed1999

Reciprocal interdependence between pineal gland and avian immune system. NEL Review.

The immune system of mammals and birds exhibits the same basic anatomical and functional organization, including dichotomy into the cellular and humoral immune response. Specificities of avian immune system may be, however, very useful for understanding numerous phylogenetic and evolutionary mysteries. Similarities and differences between mammals and birds in terms of several pineal gland functions are well known, and they seem to include the immunomodulatory activity of melatonin (MEL) as well. Embryonic pinealectomy of the chicken demonstrated functional interrelationships between the development of the pineal gland, immune system and/or neuroendocrine network, and embryonic bursectomy influenced the diurnal rhythm of the pineal gland function and abolished the effect of immunization on serum MEL level. Also immunization with a thymo-dependent antigen (SRBC) evoked some changes in the chicken nocturnal pineal NAT activity. We have found that the pineal gland and MEL control the diurnal rhythm of immunity in the chicken, but we were not able to demonstrate any immunostimulatory and anti-glucocorticoid MEL effects, regardless of the chicken's age, sex, season, and hormone dose used. The existence of functional connections between the pineal gland and the immune system in chickens was, however, confirmed in other experimental approaches. Specific and reversible binding of 2-[125I]iodoMEL to the membrane preparations from lymphoid glands was demonstrated in several avian species. In vitro MEL diminished lymphocyte proliferation stimulated by the common T-cell mitogens, while alone failed to influence the blast formation. Reciprocal functional connections between the avian immune system and the pineal gland seem to be well documented, but the mechanism(s) involved have to be elucidated.

Journal Article↗