Juvenile Age Groups Research Articles

Sexual dimorphism in the Hungarian golden jackal population: analysing body and skull size and shape

AbstractDefining species within the Canidae family is challenging due to morphological convergence, behavioral plasticity, traditional taxonomic limitations, and possible hybridisation. This challenge is timely with the recent population and range expansion of the golden jackal (Canis aureus). Exploring their morphological data and sexual dimorphism is essential for identifying factors driving their success in new habitats. The proven hybridization of golden jackals with dogs and wolves may affect species description, population dynamics, and genetic diversity, impacting conservation strategies. This study, for the first time, conducts a morphometric analysis of golden jackals in Somogy County, Hungary, to prove sexual size dimorphism (SSD) in body and skull and sexual shape dimorphism (SShD) in skull across juvenile and adult age groups. 719 golden jackals (362 females and 357 males) were collected between January 2021 and January 2023. Descriptive statistics revealed significant SSD in body and skull measurements among both age groups, with males generally larger than females, particularly in body mass (11.72% in juveniles and 13.37% in adults). Most skull dimensions differed significantly between sexes and age groups, except for foramen magnum height, foramen magnum width, and postorbital breadth among juveniles and foramen magnum height and postorbital breadth among adults. We used principal component analyses (PCA) on raw dimension data and the log shape ratio method to extract shape information. Linear discriminant analysis (LDA) explored skull SShD between sexes. Notably, our study achieved over 71% accuracy in sex classification, illustrating the clear presence of SShD of the skull in golden jackals across both age groups. Our study provides a comprehensive database of golden jackals in the overpopulated Hungarian habitat, which will be helpful for further research on ecology, behavior, and conservation management.

Glucocorticoid concentration and parasitic load in a wild striped hyaena (Hyaena hyaena) population in Southern India

Glucocorticoid levels (GCs) are an important parameter that infers the pathological condition of an organism. GCs can vary with life history stages like gender, age, and reproductive stage and signify the degree of allostatic load experienced. Deleterious increases in GCs can severely affect the wildlife population by suppressing the reproductive viability of individuals and may cause immunosuppressive, making the population more susceptible to parasitic load. We have studied the stress physiology and parasitic load across the life history stages in the striped hyaena population confined to the Moyar Valley of Mudumalai and Sathyamangalam Tiger Reserves. The fecal glucocorticoid metabolite concentrations were measured using cortisol enzyme immunoassay from 30 scats. Collected scats were categorized into adults, sub-adults, and juvenile age groups based on the size and colour of droppings. Sex of the scat samples was identified post-DNA extraction from their epithelial lining cells. Parasitic load from scats was quantified as the number of different parasites recorded through sucrose floatation and sedimentation techniques. We found no significant difference in GCs concentration and parasitic load across the life history stages, but juveniles were recorded to have the least parasitic load. The highest GCs concentration and parasitic load were recorded from adults and female individuals, while both parameters were found least among juvenile individuals. Though we did not observe any significant differences across life-history stages, this study provides the first baseline information on stress physiology and parasitic load in striped hyaenas, which could help further studies assess the impact of external perturbations on stress physiology.

Optimal Contribution Selection in Highly Fecund Species With Overlapping Generations.

Optimal contributions approaches to parental selection in closed breeding populations aim to maximize genetic gains, while restraining long-term inbreeding. The adoption of optimal contribution selection (OCS) in highly fecund outcrossing species presents a number of challenges not applicable to species of low fecundity (e.g., livestock) for which they were developed. This is particularly true if overlapping-generations or rolling-front breeding strategies are applied, in which case the number of individuals per family in juvenile (i.e., sexually immature) age groups is not necessarily known but is likely to be large. In these circumstances, conventional OCS procedures must be modified or a large number of dummy individuals defined, making computations onerous. Here, an approach to OCS is presented that involves the use of “between-family relationship matrices” instead of “between-individual relationship matrices.” The method is applicable to breeding programs involving highly fecund outcrossing species with overlapping generations, including circumstances where the number of juveniles per family is unknown but large.

PEMANFAATAN RUANG VERTIKAL PADA AKTIVITAS HARIAN ORANGUTAN (Pongo pygmaeus wurmbii) DI STASIUN RISET CABANG PANTI TAMAN NASIONAL GUNUNG PALUNG, KALIMANTAN BARAT

Orangutans are solitary animals from the Pongidae family. There are three sub-species of Bornean orangutans, i.e. Pongo pygmaeus wurmbii, P. pygmaeus pygmaeus and P. pygmaeus morio, all of which are highly endangered. Orangutans carry out several daily activities such as eating, moving, resting, and nesting in the tree canopy. However, it has yet remains unknown on how their behaviours vary with tree height. This study aimed to determine the frequency of presence, daily activities of orangutans, and vertical space utilization in orangutan activities in the natural habitat of the Panti Branch Research Station, Gunung Palung National Park. This study used the Focal Animal Sampling method with a two minute time interval for ± 12 hours and was studied for over six months. The focal orangutans whose activities were recorded during the study consisted of 12 individuals divided into 3 age groups, namely the adult, adolescent, and juvenile age groups. The results showed that the daily activity of orangutan was observed on 36 species of trees with the greatest frequency found on Garcinia sp. and Syzigium sp. accounted for33% each. The female orangutans were found to be more dominant in feeding activities (3.93 per day), while male orangutans spent more time for resting activities (4.56 hours per day). The utilization of vertical space in young male orangutans took place in tall trees and eating activities occurred at an altitude of 33.6 m. On average, teenage female orangutans choose tree to make their nests in trees 30 m high.

189 Choices ahead for dairy cattle breeding programs

Abstract Dairy cattle breeding programs have been transformed from conventional progeny-testing schemes to genomic selection paired with nucleus herd breeding in the span of one decade. This was spurred by the simultaneous advances in low-cost SNP genotyping, genomic selection methodology and reproductive biotechnologies. The rates of genetic progress have approximately doubled in this time but so have increases in inbreeding levels. This was driven by intense competition between AI studs and farmer adherence to common selection indices which has concentrated selection on very elite segments of juvenile age groups. This has led to speculation on the need for alternative indices and selection for novel traits in order to differentiate breeding programs and customize selection for unique farm conditions. This will be made more possible by the advent of on-farm sensor technology and artificial intelligence algorithms. Large commercial dairies are increasingly experimenting with crossbreeding with varying levels of success and this will require a new approach by breeding programs to focus both on purebred and crossbred performance. In addition, the potential exists for use of gene-editing to further enable value-added traits to be added into breeding programs. In parallel with breeding program advancements, consumer trends are also changing to include more interest in specialty dairy products with implied differences in digestibility, health or environmental impacts. Identifying technologies and traits that will add value either on the farm as well as at the consumer level will be a challenge for today’s breeders and producers. Some new technologies, such as gene editing, can pose consumer acceptance challenges if they are perceived to be used carelessly or for the wrong reasons. Careful choices will need to be made to continue to improve profitability, functionality and health of dairy cattle while also meeting higher consumer standards for animal welfare, health and the environment.

Psychopharmacological Options in the Multidisciplinary and Multidimensional Treatment of Eating Disorders

Eating Disorders (ED) are a syndrome characterized by persistent alteration of eating behavior and the conditions that cause insufficient ingestion and/or adsorption of foods. There are three different ED diseases: Anorexia Nervosa (AN), Bulimia Nervosa (BN) and Binge Eating Disorders (BED). ED are complex conditions that arise from a combination of long-standing behavioral, emotional, psychological, interpersonal, and social factors. A common trait to all EDs is the incongruous diet, often based on arbitrary parameters, disconnected from physiological needs, with a strong alteration of the sensations of hunger and satiety, to which variations in weight, body composition, health status and quality of life of patients occur. Although EDs are relatively frequent psychiatric disorders in the general population, especially in adolescent and juvenile age groups, evidence based on the scientific evidence of the efficacy of the pharmacological treatment of EDAs remains modest. The currently available international guidelines related to the pharmacological treatment of EDs are currently few and not always adequately informative, as they are affected by the lack of studies on the subject. As a further consequence of this it is not surprising that, with the sole exception of fluoxetine for the treatment of Bulimia Nervosa (BN) symptoms, no psychopharmaceutical has been authorized by national and international regulators for the treatment of ED. This narrative review focuses on the advantages and limitations of drugs used in the treatment of ED.

Bilateral Giant Fibroadenoma of The Breast: A Case Report

Background: fibroadenoma of the breast is one of the ANDI (Aberration of the Normal Development and Involution of the Breast) groups. Benign breast disorders are common in females younger than 30 years, but such masses are not common in juvenile or pre-menarche age groups. The exact pathological diagnosis can be investigated after surgery. For treatment, surgical procedures are needed to remove the lump. Case: a 30-year-old girl visited the outpatient clinic with psychological distress due to the presence of lumps in her both breasts. The lumps have been growing bigger and bigger in the last 3 years. On the physical examination both breasts are huge. FNAB showed the interpretation of atypical ductal hyperplasia and excisional biopsy examination confirmed the presence of bilateral giant fibroadenoma of breast. In this patient, the treatment was carried out in two-staged surgery due to her initial rejection to undergo total breast lumps and tissue removal. Several lumps still remained in the right breast which was indicated for the second surgery. The following surgery was done to remove all of the lumps and breast tissue with reduction breast surgery. Conclusion: conducting breast surgery on the young girl or un-married is not easy as many physical and psychology problems should be considered. Therefore, conducting breast surgery, in this case, should be performed wisely as the recurrence of the lumps was still possible.

ЗМІНИ ПОТУЖНОСТЕЙ ЕЛЕКТРИЧНОЇ АКТИВНОСТІ МОТОРНОЇ ЗОНИ КОРИ ГОЛОВНОГО МОЗКУ САМОК ЩУРІВ РІЗНОГО ВІКУ

Introduction . The electrical activity of the cerebral cortex reflects complex processes of reception and processing of afferent information, as well as the functional state of the organism and the level of metabolic processes. At present bioelectric activity of the motor zone of the cerebral cortex of rats during the age-related involution is not sufficiently investigated. Since most authors investigate only rats of juvenile and young age. The question of the dynamics of the indicators of electrocorticogram is a promising and relevant direction of research, which allows us to reveal the general physiological mechanisms that arise in the process of ontogenesis. Purpose To establish age changes of indicators of bioelectric activity of the motor zone of the cerebral cortex of female rats. Methods . Experiments were performed on white nonlinear, non-racially mature female rats divided into four groups by age. The registration of the electrocortichogram of the motor zone of the cerebral cortex was carried out by the method of removing the stereotactic potential, on a standard electrophysiological device. A needle unipolar electrode (nichrome diameter of 100 μ m) was used. In the total amount of electro corticochograms, the indicators of absolute and normalized power of the electric activity of the neocortex were analyzed. Results The analysis of the results of the studies showed that beta-like activity dominated among females of all age groups, in addition to the group of females of juvenile age, based on the absolute power of the motor zone of the cerebral cortex. Absolute power of delta rhythm among females of a mature age significantly increased in 3 and 7,3 times relative to the parameters of this rhythm of females of juvenile and young age. In the group of pre-adolescence, this rhythm was 32% lower than that of females of mature age. The highest rate of absolute power of theta-rhythm was among females of mature age. In the juvenile and pre-elder age, the absolute power of alpha-like activity was similar and was 3,76 ± 1.3 μ V 2 . This indicator among females of young age was significantly higher in 5,9 times with respect to juvenile age groups. In the mature age, the absolute index of alpha-like rhythm is 3,7 times higher in relation to the juvenile age group and 57% lower than in the group of younger females. Beta-like activity at the younger age decreased by 16,6% relative to females of juvenile age. In the mature age, this indicator is significantly higher at 3,5 and 4,25 times with respect to the juvenile and younger age groups. In pre-instar age, the absolute power of beta-like activity is reliably higher than 4,6 and 1,32 times in relation to the parameters of juvenile and mature age females. For normalized indices, juvenile females were dominated by delta activity of 51,1% and synchronization of rhythms was observed. The beta-like rhythm predominated in the following three age groups, the highest value of which was in rats of pre-instinctive age – 70,18%. Due to the dominance of high-frequency low-amplitude waves, females of young, mature, and pre-adolescent age observed desynchronization of rhythms. Originality The absolute and normalized indices of the motor zone of the cerebral cortex of female rats of juvenile, young, mature and pre-period periods were studied. Conclusion For indicators of absolute and normalized power, females of the juvenile age were dominated by delta activity and synchronization of biorhythms of the motor zone of the cerebral cortex was observed. At young age, the values of absolute power declined and beta-like activity predominated as a percentage, resulting in desynchronization of rhythms. In mature and pre-adulthood, females had high activity in the delta and beta-like rhythm. For normed indicators, beta-like activity and desynchronization of rhythms of neocortex in rats of mature and pre-instar age predominated.

Age-Dependent Changes of Monocarboxylate Transporter 8 Availability in the Postnatal Murine Retina.

The thyroid hormones (TH) triiodothyronine (T3) and its prohormone thyroxine (T4) are crucial for retinal development and function, and increasing evidence points at TH dysregulation as a cause for retinal degenerative diseases. Thus, precise regulation of retinal TH supply is required for proper retinal function, but knowledge on these mechanisms is still fragmentary. Several transmembrane transporters have been described as key regulators of TH availability in target tissues of which the monocarboxylate transporter 8 (MCT8), a high affinity transporter for T4 and T3, plays an essential role in the central nervous system. Moreover, in the embryonic chicken retina, MCT8 is highly expressed, but the postnatal availability of MCT8 in the mammalian retina was not reported to date. In the present study, spatiotemporal retinal MCT8 availability was examined in mice of different age. For this purpose, we quantified expression levels of Mct8 via Real-Time Reverse-Transcriptase PCR in mouse eyecups (C57BL/6) of juvenile and adult age groups. Additionally, age-dependent MCT8 protein levels were quantified via Western blotting and localized via immunofluorescence confocal microscopy. While no difference in Mct8 expression levels could be detected between age groups, MCT8 protein levels in juvenile animals were about two times higher than in adult animals based on Western blot analyses. Immunohistochemical analyses showed that MCT8 immunoreactivity in the eyecup was restricted to the retina and the retinal pigment epithelium. In juvenile mice, MCT8 was broadly observed along the apical membrane of the retinal pigment epithelium, tightly surrounding photoreceptor outer segments. Distinct immunopositive staining was also detected in the inner nuclear layer and the ganglion cell layer. However, in adult specimens, immunoreactivity visibly declined in all layers, which was in line with Western blot analyses. Since MCT8 was abundantly present in juvenile and about twofold lower in adult retinae, our findings suggest a pivotal role of MCT8 especially during postnatal maturation. The present study provides novel insights into age-dependent retinal TH supply, which might help to understand different aspects regarding retinal development, function, and disorders.

Growth Model Selection and its Application for Characterizing Life History of a Migratory Bull Trout (Salvelinus confluentus)Population

Abstract Five growth models were evaluated for their effectiveness in characterizing growth of an isolated population of bull trout, Salvelinus confluentus, undergoing a long term cessation of harvest (1994–2005) in the North Fork Clearwater River, Idaho, above Dworshak Dam. To explore the dynamics of growth in migratory bull trout, one of the models, the von Bertalanffy model, was also fitted based on age estimates derived from annuli and growth increments on pelvic fin ray sections for three juvenile outmigration age groups. Among five growth models evaluated, four models fitted to the age-length data described the fish growth for ages 3 to 11 comparably well. Only a model that exhibited positive growth acceleration as age progressed fitted the data less effectively. Growth was significantly (P < 0.001) related to the age of outmigration from natal streams (1–3 years). Migratory bull trout were found to reach maturation at ages 4–6; the common age-4 maturation was younger than most comparable studies. A...

Echocardiographic parameters for assessing successful balloon mitral valvuloplasty in juvenile age groups.

Different echocardiographic parameters have been studied and validated for assessing the severity of mitral stenosis; however, scant data are available for these markers in the context of balloon mitral valvuloplasty in juvenile age groups (ages ⩽20 years). The aim of the present study was to find out the utility of echocardiographic parameters such as mitral valve separation index, left atrial volume, right ventricular systolic pressure, tricuspid annular plane systolic excursion, tricuspid annular systolic velocity, and right ventricular Tei index in predicting success of balloon mitral valvuloplasty and their relation to mitral valve area in juvenile mitral stenosis. We carried out a prospective single-centre study involving 52 juvenile mitral stenosis patients undergoing elective valvuloplasty. Success was defined as an increase in mitral valve area ⩾50% or ⩾1.5 cm2. Echocardiographic measurements were taken before and 24 hours after the procedure and statistical analyses were carried out. The mean age of the study population was 14.3 years (SD ±4.55), ranging from 7 to 20 years. Valvuloplasty was successful in 49 out of 52 patients. The mean valve area improved from 0.89 (SD ±0.16) to 1.73 (SD ±0.22) cm2/m2 (p<0.01), and the mean mitral valve gradient decreased from 19.87 (SD ±7.89) to 7.45 (SD ±2.07) (p=0.021). All the surrogate parameters improved favourably after valvuloplasty (p<0.01). The decrease in right ventricular systolic pressure was a better indicator of the success followed by the increase in valve separation index (area under the curve 0.81 and 0.76, respectively). All the surrogate markers studied showed favourable improvement, and right ventricular systolic pressure reduction and improved mitral valve separation index were better indicators of successful valvuloplasty.

An isolated retrieval trial before extinction session does not prevent the return of fear

Several studies have shown that an isolated retrieval trial before the extinction session (retrieval-extinction) prevents the return of fear memory by inhibition of reconsolidation. Other studies have reported that retrieval-extinction did not prevent the return of the fear. To date, it is still unclear whether retrieval-extinction prevents the return of the original fear memory. A previous study revealed that reconsolidation of conditioned fear memory was not induced by the brevity of the retrieval session. Thus, we examined whether the number of retrievals in the retrieval-extinction paradigm was involved in the prevention of return of fear (Experiment 1). Furthermore, studies with different-age experimental subjects have shown conflicting results. We investigated the potential impact of age on the inhibitory effect of retrieval-extinction on the return of fear (Experiment 2). Our major findings were as follows: (1) Retrieval-extinction procedure did not prevent the return of fear, regardless of the intensity (number of presentations) of the stimulus inducing retrieval of fear memory. (2) The mice in both juvenile and adult age groups (4 and 8 weeks old) retrieved fear memory after retrieval-extinction. These results suggest the possibility that extinction after retrieval does not inhibit reconsolidation of previously consolidated fear memory.

Method of Lower and Upper Solutions for Elliptic Systems with Nonlinear Boundary Condition and Its Applications

We develop the method of lower and upper solutions for a class of elliptic systems with nonlinear boundary conditions. As its application, an elliptic system modeling a population divided into juvenile and adult age groups is studied, and we find sufficient conditions in terms of the principal eigenvalue of the corresponding linearized system, to guarantee the existence of coexistence states of the above juvenile-adult model.

On a System Modelling a Population with Two Age Groups

A system of first order ordinary differential equations describing a population divided into juvenile and adult age groups is studied. The system is not cooperative but its linear part is, and this makes it possible to establish the existence and nonexistence results of positive solutions for the system in terms of the principal eigenvalue of the corresponding linearized system.

English

&nbsp; There is evidence of&nbsp;Helicobacter pylori&nbsp;infection that induces eye diseases. This study was done to find if there is any association between&nbsp;H.&nbsp;Pylori&nbsp;and ocular diseases, and if there is any difference in color of eye among them.&nbsp;Of all&nbsp;the&nbsp;35 patients&nbsp;tested for&nbsp;biopsy with positive&nbsp;H.&nbsp;pylori, 23 (65.7%)&nbsp;were&nbsp;females and 12 (34.3%), males. The mean age of patients was 39.65&plusmn;18.55 years.&nbsp;20 (57.1%) patients were below 40 years old; 8 (22.9%) patients, 40 to 60 years and only 7 patients were more than 60 years old.&nbsp;Most of the patients were 20 years old and had no ophthalmic or systemic diseases in juvenile age group; most of them with the best correct vision were within normal measure, except the old patients who had normal tension glaucoma and two cataract cases.&nbsp;Brown eyes were the commonest but blue color was the least without any risk of ocular diseases or&nbsp;H. Pylori&nbsp;associated with more prevalent brown iris color in study group. Ophthalmic extragastric diseases do not show any association between eye diseases and&nbsp;H. pyloriinfection in juvenile age groups. Pesudoexfolitive glaucoma and two cases of cataract were among the old age related diseases which may be due to the late appearance of&nbsp;H. pylori&nbsp;effect. Best visual acuity, cup/disc character and brown color were the most associated finding. &nbsp; Key words:&nbsp;Helicobacter pylori, extragastric manifestations,&nbsp;ophthalmic&nbsp;diseases. &nbsp

Analysis of Preexistent Vertebral Rotation in the Normal Infantile, Juvenile, and Adolescent Spine

Vertebral rotation was systematically analyzed in the normal, nonscoliotic thoracic spine of children aged 0 to 16 years. Subgroups were created to match the infantile, juvenile, and adolescent age groups according to the criteria of the Scoliosis Research Society. To determine whether a distinct pattern of vertebral rotation in the transverse plane exists in the normal, nonscoliotic infantile, juvenile, and adolescent spine. We assume that, once the spine starts to deteriorate into a scoliotic deformity, it will follow a preexisting rotational pattern. Recently, we identified a rotational pattern in the normal nonscoliotic adult spine that corresponds to the most common curve types in adolescent idiopathic scoliosis. In infantile idiopathic scoliosis, curves are typically left sided and boys are affected more often than girls, whereas in adolescent idiopathic scoliosis, the thoracic curve is typically right sided and predominantly girls are affected. The present study is the first systematic analysis of vertebral rotation in the normal children's spine. Vertebral rotation in the transverse plane of T2-T12 was measured by using a semiautomatic method on 146 computed tomographic scans of children (0-16 years old) without clinical or radiologic evidence of spinal pathology. Scans were mainly made for reasons such as recurrent respiratory tract infections, malignancies, or immune disorders. Vertebral rotational patterns were analyzed in the infantile (0-3-year-old), juvenile (4-9-year-old), and adolescent (10-16-year-old) boys and girls. In the infantile spine, vertebrae T2-T6 were significantly rotated to the left (P < 0.001). In the juvenile spine, T4 was significantly rotated to the left. In the adolescent spine, T6-T12 were significantly rotated to the right (P ≤ 0.001). Rotation to the left was more pronounced in infantile boys than in the girls (P = 0.023). In juvenile and adolescent children, no statistical differences in rotation were found between the sexes. These data support the hypothesis that the direction of the spinal curve in idiopathic scoliosis is determined by the built-in rotational pattern that the spine exhibits at the time of onset. The well-known predominance of right-sided thoracic curves in adolescent idiopathic scoliosis and left-sided curves in infantile idiopathic scoliosis can be explained by the observed patterns of vertebral rotation that preexist at the corresponding age.

Persistent pruritic papules and plaques: a characteristic histopathologic presentation seen in a subset of patients with adult‐onset and juvenile Still's disease

'Persistent pruritic papules and plaques' of Still's disease represents a recently described eruption seen in a subset of patients. Most cases reported in the literature to date have been associated with adult-onset Still's disease. We present the clinical and histopathologic examinations of three female patients ranging in age from 15 to 54 years. Our three patients each presented with clinical findings consistent with Still's disease. The youngest patient suffered from the juvenile form of Still's disease (systemic-onset juvenile rheumatoid arthritis). Each patient had a persistent, pruritic eruption with histopathologic findings of dyskeratosis confined to the upper layers of the epidermis as well as a sparse superficial dermal infiltrate containing scattered neutrophils. These cases confirm the characteristic clinical and histopathologic findings of 'persistent papules and plaques of Still's disease' and show the potential for this eruption in both the adult and juvenile age groups.

Natural infection with two genotypes of Cryptosporidium in red squirrels (Sciurus vulgaris) in Italy

We investigated the genotypes of Cryptosporidium infecting red squirrels (Sciurus vulgaris L.) in two areas of the Western Alps in Italy. Examination of 141 faecal samples from 70 red squirrels revealed oocysts of Cryptosporidium in 17 animals (24.3%). Based on 18S rRNA gene sequencing, two genotypes of Cryptosporidium species were found: 15 squirrels were positive for the Cryptosporidium ferret genotype and 2 for the Cryptosporidium chipmunk genotype I. The occurrence and intensity of Cryptosporidium infection did not differ between the study areas or sex. More than 85% of the positive animals were adults; however no difference was found between Cryptosporidium infection in the juvenile and adult age groups. Oocysts of the Cryptosporidium ferret genotype measured 5.5 +/- 0.3 x 5.2 +/- 0.2 microm (shape index 1.06) and the Cryptosporidium chipmunk genotype I 5.8 +/- 0.3 x 5.4 +/- 0.3 microm (shape index 1.07). Neonatal and adult CD1 and BABL/c mice inoculated with 1 x 10(3) fresh oocysts of both genotypes did not produce detectable infection.

Emergence of brain‐derived neurotrophic factor‐induced postsynaptic potentiation of NMDA currents during the postnatal maturation of the Kölliker–Fuse nucleus of rat

The Kölliker-Fuse nucleus (KF) contributes essentially to respiratory pattern formation and adaptation of breathing to afferent information. Systems physiology suggests that these KF functions depend on NMDA receptors (NMDA-R). Recent investigations revealed postnatal changes in the modulation of glutamatergic neurotransmission by brain-derived neurotrophic factor (BDNF) in the KF. Therefore, we investigated postnatal changes in NMDA-R subunit composition and postsynaptic modulation of NMDA-R-mediated currents by BDNF in KF slice preparations derived from three age groups (neonatal: postnatal day (P) 1-5; intermediate: P6-13; juvenile: P14-21). Immunohistochemistry showed a developmental up-regulation of the NR2D subunit. This correlated with a developmental increase in decay time of NMDA currents and a decline of desensitization in response to repetitive exogenous NMDA applications. Thus, developmental up-regulation of the NR2D subunit, which reduces the Mg(2+) block of NMDA-R, causes these specific changes in NMDA current characteristics. This may determine the NMDA-R-dependent function of the mature KF in the control of respiratory phase transition. Subsequent experiments revealed that bath-application of BDNF progressively potentiated these repetitively evoked NMDA currents only in intermediate and juvenile age groups. Pharmacological inhibition of protein kinase C (PKC), as a downstream component of the BDNF-tyrosine kinase B receptor (trkB) signalling, prevented BDNF-induced potentiation of NMDA currents. BDNF-induced potentiation of NMDA currents in later developmental stages might be essential for synaptic plasticity during the adaptation of the breathing pattern in response to peripheral/central commands. The lack of plasticity in neonatal neurones strengthens the hypothesis that the respiratory network becomes permissive for activity-dependent plasticity with ongoing postnatal development.

Developmental changes in brain‐derived neurotrophic factor‐mediated modulations of synaptic activities in the pontine Kölliker–Fuse nucleus of the rat

The Kölliker-Fuse nucleus (KF), part of the respiratory network, is involved in the modulation of respiratory phase durations in response to peripheral and central afferent inputs. The KF is immature at birth. Developmental changes in its physiological and anatomical properties have yet to be investigated. Since brain-derived neurotrophic factor (BDNF) is of major importance for the maturation of neuronal networks, we investigated its effects on developmental changes in the KF on different postnatal days (neonatal, P1-5; intermediate, P6-13; juvenile, P14-21) by analysing single neurones in the in vitro slice preparation and network activities in the perfused brainstem preparation in situ. The BDNF had only weak effects on the frequency of mixed excitatory and inhibitory spontaneous postsynaptic currents (sPSCs) in neonatal slice preparations. Postnatally, in the intermediate and juvenile age groups, a significant augmentation of the sPSC frequency was observed in the presence of 100 pm BDNF (+23.5+/-12.6 and +76.7+/-28.4%, respectively). Subsequent analyses of BDNF effects on evoked excitatory postsynaptic currents (eEPSCs) revealed significant enhancement of eEPSC amplitude of +20.8+/-7.0% only in juvenile stages (intermediates, -13.2+/-4.8%). On the network level, significant modulation of phrenic nerve activity following BDNF microinjection into the KF was also observed only in juveniles. The data suggest that KF neurones are subject to BDNF-mediated fast synaptic modulation after completion of postnatal maturation. After maturation, BDNF contributes to modulation of fast excitatory neurotransmission in respiratory-related KF neurones. This may be important for network plasticity associated with the processing of afferent information.