Biomedical subjects

A Arce

Publications and source records attributed to A Arce.

At least 19 recordsLinked to original sources

PubMed2000

Differential effect of interferon-gamma injection on mitogenic responses in sympathetically denervated submaxillary lymph nodes of rats.

This study aimed to assess the effect of interferon (IFN)-gamma treatment on mitogenic responses in submaxillary lymph nodes in the presence or absence of local sympathetic nerves. Adult male rats were subjected to a unilateral superior cervical ganglionectomy and to a contralateral sham-operation. Seven days later, rats received five i.p. daily injections of human IFN-gamma (10(5) U.I./kg) or saline. On the day after the last injection, rats were killed at six different times throughout a 24-h cycle and the mitogenic effect of lipopolysaccharide (LPS) and concanavalin A (Con A) was assessed in single-cell suspensions of lymph nodes. In vehicle-treated rats, proliferation responses to LPS in innervated lymph nodes did not show time-of-day variations while those in denervated lymph nodes attained a maximum at 17:00 h. Following IFN-gamma administration, a promoting effect of LPS mitotic response was detected at 01:00 h at the innervated side only. As far as the mitogenic responses to Con A, proliferation in innervated lymph nodes of vehicle-treated controls attained a maximum at 09:00 h. Such a daily variation in response to Con A was not detectable at the denervated side. IFN-gamma treatment increased significantly Con A activity by promoting a greater mitogenic response at 01:00 h. Sympathetic denervation of lymph nodes brought about a shift in the maximum in number of cells per mg of lymph node from 21:00 to 13:00 h. After IFN-gamma treatment, maxima in cell number occurred at 05:00 h at both the innervated and denervated side. The results indicate that IFN-gamma effects in rat submaxillary lymph nodes are under substantial modulation by local sympathetic nerves.

Animals↗

PubMed2000

Time-dependent effect of cyclosporine on mitogenic responses and lymphocyte subset populations in rat spleen and submaxillary lymph nodes.

Lipopolysaccharide (LPS)- and concanavalin A (ConA)-induced proliferation and T lymphocyte subsets were measured in spleen and submaxillary lymph nodes of male rats injected with cyclosporine (5 mg/kg s.c. for 5 days, at 12.00 or 24.00 h; animals kept under light from 08.00 to 20.00 h daily). One hour before the third injection, Freund's complete adjuvant or its vehicle was administered. A suppressive effect of cyclosporine on the mitogenic action of LPS was seen in the spleen of rats injected with cyclosporine at noon whereas the effect of ConA remained unaffected. CD4+, CD8+ and CD4+-CD8+ cells decreased in spleen and lymph nodes of Freund's adjuvant-injected rats only with cyclosporine given at noon. The results further support occurrence of time-of-day-dependent effects of cyclosporine on lymphocyte subsets and proliferation.

Animals↗

PubMed1999

T-maze behaviour in domestic chicks: a search for underlying variables.

We investigated whether contrasting T-maze behaviour shown by domestic chicks, Gallus gallus domesticus, of a broiler strain reflected underlying differences in their general activity levels, fearfulness or sociality. The time taken by 2-day-old chicks to traverse a T maze and thereby regain visual contact with their companions was measured. Chicks were categorized according to whether they completed this task quickly (HP, high performance, <25 s) or slowly (LP, low performance, >75 s) and then housed in same-category groups, each of eight chicks. In experiment 1, we compared the numbers of HP and LP chicks showing certain home cage behaviours (ambulation, standing, resting, maintenance, pecking, preening). No significant differences were found. In experiment 2, we compared the behaviour of HP and LP chicks in two tests of sociality (home cage proximity, runway) and in two tests of fear (emergence, tonic immobility). The HP chicks stayed closer together in the home cage than did their LP counterparts and they spent significantly longer near a goal box containing conspecifics in the runway than did LP ones. Conversely, there were no significant differences between HP and LP chicks in their latency to emerge from a sheltered area into an exposed and, hence, potentially frightening one or in their tonic immobility fear reactions. These findings suggest that contrasting T-maze performance was unlikely to have reflected differences in underlying activity levels or in fearfulness. Conversely, individual variation in underlying sociality was probably an influential variable. Copyright 1999 The Association for the Study of Animal Behaviour.

Journal Article↗

PubMed1999

Early T-maze behaviour and subsequent growth in commercial broiler flocks.

Two batches of 2000 mixed-sex broiler chicks were obtained, one in summer and one in winter. Each flock was housed on the floor at a commercial farm. At 2 or 3 d of age, the latencies to escape from a T-maze were measured in 1044 and 1180 chicks in the summer and winter flocks, respectively. Chicks were assigned to high (HP), moderate (MP) or low (LP) performance categories if their escape latencies were below 40 s, between 40 to 90 s, or above 90 s, respectively. Ninety male and 90 female chicks from each of the 3 categories were weighed when they were 3 d old. The birds then remained undisturbed, apart from routine maintenance, until similar numbers were weighed at 49 d of age. Some birds may have been weighed at both ages. Body weights were higher in males than females and higher in the winter than summer flock at 3 d of age. Significant main effects of chick category as well as gender and season were found at 49 d of age. There were no significant interactions. As expected, 49-d body weights were higher in males than females and in the flock reared in winter than in summer. 5. HP chicks (those that showed rapid escape from the T-maze at 3 d) were also significantly heavier at 49 d than their LP counterparts, with MP chicks occupying an intermediate position. This suggests that early performance in a T-maze test is positively associated with subsequent growth. Furthermore, this relationship was apparent in each of the 2 flocks. Given this positive association, we suggest that this simple, rapid and non-invasive behavioural test could be a useful selection criterion for future breeding programmes.

Aging↗

PubMed1998

Cyclosporine A-induced decrease in calbindin-D 28 kDa in rat kidney but not in cerebral cortex and cerebellum.

Recently, we reported that in rat, cyclosporine A (CsA) markedly decreases the levels of calbindin-D (CABP-D) 28 kDa in kidney. CABP-D 28 kDa is a calcium-binding protein which is highly expressed in calcium-transporting tissues such as kidney or brain. In this study, we investigated whether, in addition to the kidney, CsA also has an effect on CABP-D 28 kDa in rat brain. Three groups of male Wistar rats received 15 mg/kg/day or 50 mg/kg/day of CsA orally for 12 days, whereas controls received vehicle solution for the same period. CABP-D 28-kDa protein and CsA were quantified in homogenates of kidney, cerebral cortex and cerebellum, and the localization of CABP-D 28 kDa was assessed in the different tissue sections by immunohistochemistry. In kidney, CABP-D 28 kDa was strongly and dose dependently decreased, and was located in tubular epithelial cells. In brain, CABP-D 28 kDa was not changed and was mainly located in pyramidal cells of the cortex and in cerebellum exclusively in Purkinje cells. High CsA concentrations were measured in kidney, more than 17-fold greater than those found in cortex. In cerebellum, CsA was below the limit of detection. These data suggest that at clinically relevant doses, CsA may not affect CABP-D 28-kDa levels in brain.

Animals↗

PubMed1998

Effect of superior cervical ganglionectomy on catecholamine concentration in rat cochlea.

Both noradrenergic and dopaminergic nerve terminals have been described in the cochlea. The present report focused on the effect of superior cervical ganglionectomy (SCGx) on monoamine concentration in adult rat cochlea. In homogenates of whole cochleas, we measured the concentrations of norepinephrine (NE), dopamine (DA) and its main metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), by HPLC coupled to electrochemical detection. Measurements were carried out 4 h, 24 h or 6 days after unilateral SCGx. Most of the NE (approximately 82%) was lost after sympathectomy on the ipsilateral side, indicating that the principal localization of cochlear NE is in peripheral sympathetic fibers. Since about 18% of NE remained detectable 6 days after SCGx, a second origin of cochlear noradrenergic fibers may exist. Cochlear concentrations of DA or its metabolites did not change after SCGx. Therefore, DA and NE are located in two different populations of fibers within the cochlea, and are presumably related to distinct functional roles.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1998

New insights into cyclosporine A nephrotoxicity by proteome analysis.

Using two-dimensional gel electrophoresis (2-DE), we recently discovered an association between decreased calcium-binding protein, calbindin-D 28 kDa, urinary calcium wasting and intratubular corticomedullary calcifications in rat kidney. This observation prompted us to investigate kidney tissues of other species, including man. In this paper we show that in dogs and monkeys, which are generally devoid of cyclosporine A (CsA)-mediated nephrotoxicity, renal calbindin levels were not affected by the CsA treatment whereas in CsA-treated human kidney-transplant recipients with renal vascular or tubular toxicity, a marked decrease in renal calbindin-D 28 kDa protein level was found in most of the kidney biopsy sections. The present results strongly suggest that calbindin is a marker for CsA-nephrotoxicity. The discovery of calbindin-D 28 kDa being involved in CsA toxicity has evolved from the application of 2-DE and has not been reported previously, proving that proteomics can provide essential information in mechanistic toxicology. Considering the current improvements in proteome methods it is expected that high throughput proteomics will become an indispensable tool in preclinical safety testing.

Animals↗

PubMed1998

Changes in the liver protein pattern of female Wistar rats treated with the hypoglycemic agent SDZ PGU 693.

SDZ PGU 693 acts as a hypoglycemic agent by stimulating glucose utilisation in insulin-sensitive peripheral tissues, such as skeletal muscle and fat. In a 28 day toxicity study the compound was found to induce hepatocellular hypertrophy in Wistar rats treated with 300 mg/kg/day. To gain insights into the pathomechanism of these alterations, aliquots of liver samples from control and treated female Wistar rats were separated by two-dimensional protein gel electrophoresis and the digitized images of the protein patterns were searched for protein abundance changes. Significant treatment-related quantitative changes (P < 0.001) were found in 29 liver proteins. Major increases were observed in several microsomal proteins, including NADPH cytochrome P-450 reductase, cytochrome b5 and serine protease inhibitor. The changes in the cytochrome related enzymes, both known co-factors of the P-450 enzyme system, strongly suggest that SDZ PGU 693 induces microsomal proliferation and induction of the P-450 enzyme system. Decreases were observed in a series of mitochondrial proteins, such as F1ATPase-delta subunit and ornithine aminotransferase precursor as well as in several cytosolic proteins such as the liver fatty acid binding protein, arylsulfotransferase and the senescence marker protein-30. The changes in F1ATPase-delta subunit and liver fatty acid binding protein together suggest a down-regulation of the mitochondrial liver fatty acid metabolism, likely reflecting the pharmacological action of the compound. These results show that SDZ PGU 693 produces a complex pattern of gene expression changes which give insights into the molecular mechanisms of both its pharmacological action and a toxic response.

Animals↗

PubMed1998

Tachykinins in the pineal gland: effect of castration and ganglionectomy.

In this investigation, the presence of NKA-immunoreactive substances was determined in pineal glands from intact, castrated and castrated, testosterone-treated male rats. The effect of environmental light, melatonin treatment and superior cervical ganglionectomy on pineal NKA-immunoreactive substances was also investigated. The results obtained show that NKA is present in measurable amounts in the rat pineal, and NPK is probably also present, Orchidectomy was followed by an increase in the content of NKA-immunoreactive substances in the pineal gland. The replacement treatment with testosterone propionate in castrated rats blocked this effect. NKA-immunoreactive substances were not significantly different quantitatively in pineals from rats killed under light or under darkness. The removal of the superior cervical ganglia was followed by a significant increase in the NKA-immunoreactive substance content in the pineal gland of male rats. These results indicate that NKA and other tachykinins are present in the pineal gland of the male rat, and they seem to be regulated by gonadal hormones and the innervation originated from the superior cervical ganglia.

Animals↗

PubMed1998

Anxiogenic-like effects of Tagetes minuta L essential oil on T-maze and tonic immobility behaviour in domestic chicks.

In a first experiment, four doses (ranging between 0.04 and 0.45 mg/kg of body weight) of the essential oil from Tagetes minuta L. were subcutaneously injected in two-day-old chicks and a dose-response curve assessed for escape performance in a T-maze test. The 0.1, 0.25 and 0.45 mg/kg doses impaired the first escape performance suggesting an anxiogenic-like effect of the essential oil. After 3 h the same chicks were tested for a second escape performance, without being injected again, and no differences were observed compared to controls, suggesting that the essential oil did not affect retention. Furthermore, the effects of the essential oil were observed in the three sections of the T-maze apparatus. So, the performance was impaired in the isolation chamber section, suggesting the induction of increased anxiogenic behaviour, and also in the mirror section, suggesting that the social reinstatement behaviour was modified by an increased anxiety level. Changes in the principal corridor section were not observed, suggesting that the locomotor activity was not affected by these oil doses. The second escape performance was not affected in any of the T-maze sections, confirming that these doses did not affect learning ability. In a second experiment, a middle dose of the essential oil (0.25 mg/kg) increased the tonic immobility reaction in 15 days old chicks similarly to an anxiogenic dose of FG 7142 (1 mg/kg), while an anxiolytic dose of diazepam (0.08 mg/kg) did not affect this behaviour. Taken together, the present results suggest that the essential oil from Tagetes minuta L. may exert a negative modulation on the GABAergic function without affecting the learning ability.

Animals↗

PubMed1998

Development of 24-hour rhythms in serum prolactin and luteinizing hormone levels in rats neonatally administered melatonin.

To obtain information on the chronobiological consequences of neonatal melatonin administration to rats, we examined the 24h variations of serum prolactin and luteinizing hormone (LH) levels in 21-, 25-, and 60-day-old male rats injected with 100 microg of melatonin or vehicle on the fifth day of life and kept under light from 08:00 to 20:00 daily. In 21-day-old rats, circulating prolactin varied diurnally in melatonin-treated rats only, showing a maximum at 16:00 and a secondary peak at 08:00. In 25-day-old rats, both vehicle- and melatonin-injected rats exhibited significant time-of-day-related changes in serum prolactin, with 77% of the variation in melatonin-injected rats explained by a single 24h component. Acrophase for prolactin rhythm of melatonin-treated rats occurred at 19:51. At 60 days of age, rats receiving vehicle or melatonin showed similar, significant 24h variations in serum prolactin, with acrophases at 17:31-18:15. Serum LH levels attained a maximum at midnight in 21-day-old rats treated with vehicle and at noon in those injected with melatonin. After a cosinor analysis, 71% of the variation in melatonin-injected rats was explained by a single 24h component, with the acrophase at 11:08. In 25-day-old rats, a complex pattern of serum LH concentration was found, with two maxima in vehicle-injected controls, at noon and midnight, and a maximum at noon together with a plateau from 20:00 to 04:00 in melatonin-treated rats. In 60-day-old rats, the maximum of serum LH was found at noon, with a similar extent showing in vehicle- and melatonin-treated animals. The acrophases were at 10:20 (vehicle) and 10:57 (melatonin) and did not differ significantly from that found in 21-day-old melatonin-treated rats. The results suggest that exposure to melatonin early in life may accelerate maturation of 24h prolactin and LH profiles toward an adult form.

Animals↗

PubMed1998

Effects of immunoneutralization of substance P on hypothalamic neurotransmitters in normal mice and in transgenic mice expressing bovine growth hormone.

It is well known that transgenic mice expressing bovine growth hormone have altered neuroendocrine functions. Substance P was shown to influence the secretion of gonadotropins. In this investigation, the effect of a single injection of an antiserum to substance P was investigated in intact and castrated transgenic (MT-bGH) mice and in their normal litter mates. In the median eminence, the administration of antisubstance P serum resulted in a decreased dihydroxyphenyl acetic acid/dopamine index in intact and castrated normal mice but was without effect in transgenics. The homovanillic/dopamine index was decreased in normal mice (intact or castrated) but unchanged in transgenics. Norepinephrine and epinephrine were increased in normal mice (intact and castrated) treated with the anti-SP serum, but in transgenic mice, the anti-SP serum induced significant changes of norepinephrine only in intact animals, with no modifications in epinephrine levels. In the whole hypothalamus (minus the median eminence), the injection of antisubstance P serum resulted in an increased dihydroxyphenyl acetic acid/dopamine index in castrated, but not in intact, normal mice. In transgenic mice, this index was increased in intact but decreased in castrated animals. The homovanillic/dopamine index was decreased in normal intact mice treated with the antiserum but increased in intact transgenic mice. Norepinephrine and epinephrine were decreased by the antiserum treatment in normal intact mice but were unchanged in transgenics, except for norepinephrine in castrated transgenics, in which it was found increased. The administration of the antiserum did not affect plasma LH, FSH, or prolactin in normal mice but it reduced LH levels in intact transgenic mice. These results indicate that the response to the treatment with the antiserum to substance P shows considerable alterations in transgenic mice as compared with their litter-mate, normal controls, producing divergent effects on hypothalamic catecholamine metabolism. The present findings confirm that transgenic mice overexpressing the bGH gene have marked neuroendocrine alterations as compared with their normal litter mates.

Animals↗

PubMed1998

Effects of acute and chronic administration of cyclosporine on dopamine metabolism in the rat cochlea.

The effect of cyclosporine (CyA) on dopamine (DA) metabolism at the cochlear level was analyzed. Adult male rats were submitted to CyA treatment at the doses of 1, 5 or 20 mg/Kg/day, for 1 day (acute) or 8 days (chronic). Cochlear contents of DA and its metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), were measured by using high performance liquid chromatography (HPLC-ED). Either dose of acutely administered CyA did not modify cochlear DA content and markedly reduced that of DOPAC, in a non dose-dependent way. Acute administration of 5 mg/Kg of CyA decreased HVA content while the highest dose increased it. DOPAC/DA index was significantly reduced with either CyA dose, although HVA/DA index was not modified. Chronic treatment with CyA markedly reduced cochlear DA and DOPAC contents in a non dose-dependent way. However, HVA content decreased after the highest administration dose of the drug. DOPAC/DA index was further reduced after the drug chronic administration. An increased HVA/DA index was surprisingly observed, after chronic administration of either dose of the drug, the response being dose- dependent. These data show that acute treatment with CyA mainly affects the DA reuptake, while chronic treatment affected both DA reuptake and metabolism at the cochlear level.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1998

Circadian rhythms in adenohypophysial hormone levels and hypothalamic monoamine turnover in mycobacterial-adjuvant-injected rats

The effect of Freund's adjuvant injection on 24-hour variation in circulating ACTH, prolactin, growth hormone (GH) and thyroid-stimulating hormone (TSH) levels, and of hypothalamic norepinephrine (NE) content and dopamine (DA) and serotonin (5HT) turnover was examined in adult rats. In control rats, serum ACTH and prolactin exhibited peak values at the light-dark transition while the maximum in TSH was found in the late afternoon. GH levels did not vary on a 24-hour basis. In Freund's-adjuvant-injected rats, 24-hour variations in TSH levels became blunted while 24-hour variations in prolactin and ACTH persisted. Freund's adjuvant treatment augmented serum ACTH and prolactin levels, and decreased GH and TSH levels. Hypothalamic NE content, and turnover of DA and 5HT varied on a 24-hour basis in rats receiving adjuvant's vehicle. The NE content of the anterior, medial and posterior hypothalamus peaked at 04.00 h, while that of the median eminence attained its maximum at 16.00-20.00 h. Maxima in hypothalamic DA and 5HT turnover ocurred at 04.00 h regardless of the region examined. In Freund's-adjuvant-injected rats, reduced amplitude of daily variations of NE content in the median eminence and anterior and medial hypothalamus, as well as a phase advance in the 24-hour rhythm of the posterior hypothalamic NE content were seen. Mycobacterial adjuvant injection also reduced the amplitude of circadian rhythm in hypothalamic 5HT turnover, shifted the maximum in median eminence DA turnover towards light-dark transition, and decreased the amplitude of DA turnover rhythm in the anterior, medial and posterior hypothalamus. Administration of the immunosuppressant drug cyclosporine restored the augmented ACTH and prolactin levels and the depressed GH and TSH levels found in Freund's-adjuvant-injected rats. Cyclosporine was also effective to restore 24-hour rhythmicity of serum ACTH and TSH, but not of prolactin levels. Immunosuppression restored rhythmicity of NE content and of DA and 5HT turnover in anterior, medial and posterior hypothalamic regions. Cyclosporine did not modify the effect of Freund's adjuvant on median eminence but in was able to counteract the changes in the DA and 5HT turnover in the median eminence found after immunization. The results are in accord with a significant effect of immune-mediated inflammatory response at an early phase after Freund's adjuvant injection on ACTH, GH, prolactin and TSH release mechanisms, which was partially sensitive to immunosuppression induced by cyclosporine.

Journal Article↗

PubMed1998

Acute and chronic effects of superior cervical ganglionectomy on in vitro mitogenic responses of lymphocytes from submaxillary lymph nodes of pituitary-grafted rats

Male rats were grafted an anterior pituitary within breast muscles or received a sham operation on day 5 of life. At the 60th day of life, the sympathetic denervation of rat submaxillary lymph nodes was achieved by a bilateral sympathetic superior cervical ganglionectomy (SCGx; at 15.00 h). Rats were killed either 18 h later (acute SCGx) or after 12 days (chronic SCGx) to measure lipopolysaccharide (LPS)- and concanavalin A (ConA)-induced cell proliferation in submaxillary lymph nodes, submaxillary lymph node cellularity and serum prolactin levels. In control rats, acute SCGx significantly augmented LPS or ConA activity on lymph cells while chronic SCGx had no effect. In pituitary-grafted rats, acute SCGx depressed the mitogenic effect of LPS or ConA whereas chronic SCGx augmented it. A global inhibitory effect of surgical stress on submaxillary lymph node cellularity was found in rats subjected to SCGx or its sham operation 18 h earlier. Serum prolactin levels increased significantly in pituitary-grafted rats, particularly in those subjected to chronic SCGx. In pituitary-grafted rats, a significant effect of acute SCGx was apparent, with serum prolactin levels augmenting about twice in sham-SCGx rats, and to a significantly less extent in acute SCGx rats. The results provide further evidence of the immunomodulatory role of local sympathetic nerves in submaxillary lymph nodes.

Journal Article↗

PubMed1997

Learning and novelty induced increase of central benzodiazepine receptors from chick forebrain, in a food discrimination task.

Young chicks were trained to discriminate food grains from inedible pebbles. On Day 1 and Day 2 of the task, latency to peck, and number of pecks were scored and the forebrain [3H]flunitrazepam receptor binding was also determined at 0 and 30 min after an 8-min training session. Compared with quiet controls, the receptor density increased 46%, 30 min after the training session on Day 1. Compared with chicks that had learned the discrimination and were merely repeating already learned behavior on Day 2, the receptor increased more than 46%. Since chicks that had learned the discrimination had a higher behavioral activity, we interpret that the learning of a new task is itself responsible in addition to stress for the receptor density increase. Stressful factors accompanying the learning task as handling and novelty increased 17% the receptor density, 30 min after a training session without food, compared with quiet controls. However, receptor density did not increase in chicks repeating the same housing conditions, suggesting that chicks were habituated to handling and novelty on Day 2. Differences in receptor density were not observed between quiet controls and experimental groups, at 0 min after the training session, indicating that changes were time dependent. In all cases the affinity remained unchanged. Our results suggest that, the GABA(A) receptor (i) is involved in early stages of memory formation and in stress adaptive responses, and (ii) is modulated by new non-repetitive environmental conditions.

Animals↗

PubMed1997

Effect of local autonomic denervation on in vitro responsiveness of lymphocytes from rat submaxillary lymph nodes.

The local autonomic denervation of rat submaxillary lymph nodes was achieved by a unilateral sympathetic superior cervical ganglionectomy and/or the unilateral section of chorda tympani (that resulted in ipsilateral parasympathetic decentralization of the submandibular territory). This study was performed to determine: (1) whether local sympathetic and/or parasympathetic denervation of rat submaxillary lymph nodes brought about changes in lymph node cellularity, natural killer activity and lipopolysaaccharide (LPS)- and concanavalin A (Con A)-induced cell proliferation in Freund's adjuvant-injected rats; (2) whether the effect of the immunosuppressive drug cyclosporine in rat submaxillary lymph nodes was affected by a single or combined unilateral ganglionectomy plus decentralization. A unilateral ganglionectomy, or the combination of ganglionectomy plus decentralization, performed 7 days earlier, decreased significantly cellularity in ipsilateral submaxillary lymph nodes, while a unilateral decentralization failed to affect it. Natural killer activity increased ipsilaterally after ganglionectomy or decentralization, and decreased after the combined surgical procedure. LPS-induced cell proliferation augmented significantly after ganglionectomy or decentralization, while Con A-induced T lymphocyte proliferation remained unaffected. In the sham-operated side, cyclosporine decreased submaxillary lymph node cell number and natural killer activity, while it increased the proliferative response to LPS. The depressive effect of cyclosporine on lymph node cellularity was no longer observed in ganglionectomized or decentralized lymph nodes, but was found after the combined surgical denervation. Decentralization, or decentralization plus ganglionectomy, blunted the depressive effect of cyclosporine on natural killer activity. The stimulatory effect of cyclosporine on lymphocyte proliferation induced by LPS was reversed both by ganglionectomy or by decentralization and was suppressed by the combined surgical procedure. Neither treatment affected Con A-induced proliferation of T lymphocytes. The results further indicate that an appropriate sympathetic and parasympathetic local environment may be needed for immunomodulation, as well as for cyclosporine activity in lymphoid tissue.

Animals↗

PubMed1997

Effect of diazepam and A beta-carboline on open-field and T-maze behaviors in 2-day-old chicks.

The effects of diazepam and the beta-carboline FG 7142 in chicks were examined on several behavioral measures in open-field and T-maze tasks. In the open field, only the higher doses of diazepam affected behavior, suggesting a sedative-like effect, while FG 7142 influenced behavior as would a fear-inducing manipulation. After a low dose of either drug was injected, testing in a T-maze showed that diazepam improved and FG 7142 impaired the escape performance from the isolation chamber, without affecting the time spent in the T-corridor. In three groups of chicks selected on the basis of their first escape performance, only lower performance chicks were affected by an anxiolytic dose of diazepam. T-maze results suggest that: (a) T-maze is more sensitive than open-field test to behavior changes induced by anxiolytic doses of diazepam; (b) isolation chamber behavior could be an index of general emotionality in young chicks; (c) diazepam and FG 7142 do not modify the social motivation to escape the maze; (d) higher performance chicks present an escape behavior of a less anxious type than lower performance chicks. The results suggest that the GABAergic system is involved in the behavioral expression of fear and anxiety in young chicks.

Animals↗