European and United Kingdom COVID-19 pandemic experience: The same but different.

The global healthcare landscape has changed dramatically and rapidly in 2020. This has had an impact upon paediatricians and in particular respiratory paediatricians. The effects in Europe, with its mature healthcare system, have been far faster and greater than most authorities anticipated. Within six weeks of COVID-19 being declared a public health emergency by the World Health Organisation [WHO] in China, Europe had become the new epicentre of disease. A pandemic was finally declared by the WHO on March 11th 2020. Continued international travel combined with the slow response of some political leaders and a variable focus on economic rather than health consequences resulted in varying containment strategies in response to the threat of the initial wave of the pandemic. It is likely that this variation has contributed to widely differing outcomes across Europe. Common to all countries was the stark lack of preparations and initial poor co-ordination of responses between levels of government to this unforeseen but not unheralded global health crisis. In this article we highlight the impact of the first wave of the COVID-19 pandemic in Italy, Austria, Germany, and the United Kingdom.

Serum resistin levels in children with primary snoring.

Primary Snoring (PS) has been positioned at the milder end of the Sleep-Disordered Breathing severity continuum characterized by snoring and it is usually underestimated. PS is defined as snoring without apnea, frequent arousals, or gas exchange abnormalities and recent studies demonstrated that children with PS have increased blood pressure and reduced arterial distensibility. The association between adipokines and SDB has been recently investigated, though most of the studies were focused on OSAS where intermittent hypoxia characterizing the disease may lead to an inflammatory cascade and to the release of several adipokines, contributing to oxidative stress. Resistin, initially described s an adipokine increasing insulin resistance, has been recently identified as a novel important member of the cytokine family involved in the regulation of inflammation. The aim of our study was to investigate circulating resistin levels in normal weight children with PS. Sixty-five children of normal weight aged between 4 and 14 years of age were selected for habitual snoring. Children with positive polysomnography were excluded from the study. Serum resistin levels were detected in all children with PS. Thirty-three healthy non-snorer children with similar age, sex and BMI were selected as a control group. A significantly higher level of resistin was observed in patients with PS compared to the control group (4.67±1.91 ng/ml vs 3.98±1.58 ng/ml; p<0.01). Patients with inconclusive pulse oximetry showed significantly higher resistin levels than those with negative recordings recordings (5.29±1.91 ng/ml vs 4.20±1.93 ng/ml; p<0.008). Moreover, there was a significant increasing trend between sieric adipokine level and the frequency of snoring (p<0.006). Our results suggest that systemic inflammation and oxidative stress may also play a significant role in the pathophysiology of PS.

Antiandrogenic effect of perinatal exposure to the endocrine disruptor di-(2-ethylhexyl) phthalate increases anxiety-like behavior in male rats during sexual maturation.

Di-2-ethylhexyl phthalate (DEHP) is the most widely used phthalate to convey flexibility and transparency to plastic products made of polyvinyl chloride. It has been recognized as endocrine disruptor and associated with reproductive toxic effects. We examined the effects of perinatal exposure to DEHP on anxiety-like behavior, using the Elevated Plus Maze (EPM) test, in male and female rats at different stages of sexual development. Anxiety-like behavior was expressed as a) frequency of open arm entries over the total arm entries (% FEO); b) time spent in them compared with total time the animal stayed in the EPM (% TSO) and c) time spent in closed arms (TSC). Because DEHP has anti-androgenic action we also tested control and exposed immature male rats pretreated with testosterone. We found sex differences in behavior induced by DEHP; while male rats of 45 and 60 days of age showed a significant decrease in FEO and TSO percentages, as well as an increase in TSC, no changes were observed in anxiety-like behavior in perinatal DEHP exposed females at these ages of sexual maturation. In 60-day-old male rats, DEHP exposure produced a significant decrease in serum testosterone levels. Testosterone replacement was able to antagonize the adverse effects of DEHP exposure on LH, activating the negative feed-back mechanism of this steroid on reproductive axis, as well as increasing FEO and TSO percentages to similar values observed in the control group. These findings suggest that the anti-androgenic action of this chemical could be one possible mechanism underlie anxiogenic-like behavior produced by perinatal DEHP exposure in 60-day-old male rats.

Regular vs prn nebulized treatment in wheeze preschool children.

BACKGROUND: International guidelines recommend regular treatment with inhaled glucocorticoids for children with frequent wheezing; however, prn inhaled bronchodilator alone or in combination with glucocorticoid is also often used in practice. We aimed to evaluate whether regular nebulized glucocorticoid plus a prn bronchodilator or a prn nebulized bronchodilator/glucocorticoid combination is more effective than prn bronchodilator alone in preschool children with frequent wheeze. METHODS: Double-blind, double-dummy, randomized, parallel-group trial. After a 2-week run-in period, 276 symptomatic children with frequent wheeze, aged 1-4 years, were randomly assigned to three groups for a 3-month nebulized treatment: (1) 400 microg beclomethasone bid plus 2500 microg salbutamol prn; (2) placebo bid plus 800 microg beclomethasone/1600 microg salbutamol combination prn; (3) placebo bid plus 2500 microg salbutamol prn. The percentage of symptom-free days was the primary outcome measure. Secondary outcomes included symptom scores, use of relief medication and exacerbation frequency. RESULTS: As compared with prn salbutamol (61.0 +/- 24.83 [SD]), the percentage of symptom-free days was higher with regular beclomethasone (69.6%, SD 20.89; P = 0.034) but not with prn combination (64.9%, SD 24.74). Results were no different in children with or without risk factors for developing persistent asthma. The effect of prn combination was no different from that of regular beclomethasone on the primary and on several important secondary outcomes. CONCLUSIONS: Regular inhaled glucocorticoid is the most effective treatment for frequent wheezing in preschool children. However, prn bronchodilator/glucocorticoid combination might be an alternative option, but it requires further study.

Clinical evaluation and treatment of acute asthma exacerbations in children.

This update on treatment of asthma exacerbations in children is the result of an Italian Pediatric Society Task-force, made up of a panel of experts working in 2007-2008. The aim is to give clear indications on the use of the drugs most employed in children, grading the quality of evidence and the strength of recommendations. Suggestions on their limits due to unlicensed and off-label use are reported. The level of evidence and the strength of recommendations for different therapeutic approaches demonstrate that frequently the use of drugs in children is extrapolated from the experience in adults and that more studies are required to endorse the correct use of different drugs in asthmatic children.

Changes in motor function and brain cortex mitochondrial active oxygen species production in aged mice.

Neuronal ageing is a complex physiological process, associated to metabolic and motor changes. In this study, 3 and 17 months old male Swiss mice were used. Aged mice exhibited a significant reduction in motor performance and walking footprint pattern. Synaptosomes and mitochondrial fractions were isolated from mouse brain cortex. Active oxygen species and cardiolipin content were measured in both subcellular fractions. Synaptosomal acetylcholinesterase activity was measured in both animal age groups. Results showed that superoxide levels were 42.9% lower in synaptosomes from old mice as compared with young animals, while no changes were observed in non-synaptic mitochondria. Succinate-glutamate dependent H2O2 production rate was 27.5% decreased in non-synaptic mitochondria from aged mice. Cardiolipin content was 21% decreased in synaptosomes from 17-months old animals, while no changes were observed in non-synaptic mitochondria. Acetylcholinesterase activity decreased 16% in 17-months old mice, as compared with young animals. Age-related alterations in neuronal function could be associated with changes in active oxygen species at synapses, with parallel motor deficiencies.

Effect of di(2-ethylhexyl) phthalate on the neuroendocrine regulation of reproduction in adult male rats and its relationship to anxiogenic behavior: Participation of GABAergic system.

The endocrine disruptor di-(2-ethylhexyl) phthalate (DEHP) is used in a variety of consumer products made with polyvinyl chloride and also in the manufacture of medical devices. DEHP disrupts reproductive tract development in an antiandrogenic manner and also may induce neurobehavioral changes. The aim of this study was to investigate the effects of chronic postnatal exposure to DEHP (30 mg/kg body weight/day, orally from birth to day 60) on the neuroendocrine regulation of the gonadal axis and its impact on the anxiety-like behavior in adult male rats, as well as the probable participation of the GABAergic system in these effects. DEHP produced a significant increase in plasmatic luteinizing hormone and follicle stimulating hormone, as well as significant testosterone decrease, accompanied with a decrease in hypothalamic gamma-aminobutyric acid (GABA) concentration. On the other hand, DEHP increased the anxiety-like behavior in the elevated plus maze test, evidenced by a significant decrease in the percentages of time spent in the open arms and the frequency in the open arm entries and a significant increase in the percentage of time spent in closed arms. Neuroendocrine and behavioral effects were reversed by GABA agonists, muscimol (2 mg/kg i.p. ) and baclofen (10 mg/kg i.p.). In conclusion, chronic DEHP postnatal exposure induced a disruption in the neuroendocrine regulation of the testicular axis in young adult male rats, and this effect was correlated with an anxiety-like behavior. Since GABA agonists reversed these effects, the results suggest that GABA could participate in the modulation of reproductive and behavioral DEHP effects.

Authors' reply - anaphylactic shock with methylprednisolone, Kounis syndrome and Hypersitivity to corticosteroids: a clinical paradox.

In our letter, we comment the paper of Kounis et al., that highlights a poor-known clinical entity determined by systemic use of corticosteroids, the so-called "Kounis syndrome type I". We appreciated and shared the intent of Authors to treat the important issue of high risk of adverse drug reaction in patients with atopic diathesis and we confirm the need to administer corticosteroids with caution in patients suffering from allergic disease.

Correlation between cephalometric variables and obstructive sleep apnoea severity in children.

AIM: Alterations in craniofacial growth have been associated with obstructive sleep apnoea in children. The main objectives of this study were to analyse the correlation between cephalometric variables and Obstructive Apnea/Hypopnea Index (OAHI) in order to investigate if craniofacial features may influence the severity of obstructive sleep apnoea and to study the correlation between upper nasopharyngeal width and maxillomandibular skeletal discrepancy in sagittal and vertical plane. MATERIALS AND METHODS: Study Design: Correlations between cephalometric variables and obstructive sleep apnoea/hypopnea index and between upper airways space and maxillomandibular skeletal discrepancy were investigated. Forty-seven children with obstructive sleep apnoea diagnosed by overnight sleep study (polysomnography) underwent a lateral radiograph, orthodontic and ear-nose-throat examinations. Cephalometric analysis according to Kirjavainen has been performed to define skeletal and upper airways variables. STATISTICS: Spearman's correlation analysis was performed between OAHI and all cephalometric variables. Pearson's correlation analysis was performed between cephalometric variables of upper airway space and cephalometric variables related to maxillomandibular discrepancy. Chi-square test was used to compare occlusal features with adenoidal and tonsillar hypertrophy. Kruskal-Wallis rank test was used to compare OAHI with occlusal variables and adenotonsillar hypertrophy. RESULTS: The results show a positive correlation between OAHI and maxillomandibular discrepancy measured by ANB angle (rho=0.32; p=0.023). A significant correlation was found between upper nasopharyngeal width and vertical maxillomandibular skeletal discrepancy: 1) ad1-PNS were correlated to Mandibular Plane/Sella- Nasion angle (r=-0.36; p=0.012), Palatal Plane/Mandibular Plane angle (r=-0.39; p=0.007), and Posterior-Anterior Facial Height % (r=0.29; p=0.045); 2) ad2-PNS was correlated to Palatal Plane/Mandibular Plane angle (r=-0.39; p=0.007). No statistically significant differences were found in non-parametric tests between OAHI and occlusal variables or adenoidal and tonsillar hypertrophy. CONCLUSIONS: The present study shows a significant correlation between maxillomandibular discrepancy and the severity of OSA. Moreover, the reduction of nasopharyngeal width was correlated to maxillomandibular hyperdivergent growth pattern. These results support the presence of a correlation between sleep-disordered breathing and craniofacial features even if the cause-effect relation is still unclear. Based on these evidences, we suggest the importance of orthodontic evaluation in the management of paediatric OSA.

A survey around the Italian pediatric units on current clinical practice for Sleep Disordered Breathing (SDB).

BACKGROUND: During recent years, interest on Sleep Disordered Breathing (SDB) in pediatric age has increased, due to the impact on quality of life, psycho-physical attitude and other serious morbidities if undiagnosed and untreated. METHODS: Italian Pediatric Respiratory Diseases Society (SIMRI) SDB-Working Group carried out an exploratory survey in Italy, from January to December 2016, to assess the diagnostic and therapeutic pathways, perception and relevance of SDB in Italian Hospitals. RESULTS: A questionnaire was sent to 180 Pediatric Units (PUs) distributed throughout the Italy; 102 Pediatric Units (PUs; 56.6%) answered and among them 57% dealt with SDB, and 94% recognized SDB as a major problem. Instrumental tests performed by the PUs were saturimetry (66%), nocturnal polygraphy with complete cardio-respiratory monitoring (46%) and full polysomnography (23%). In addition, hospital pediatricians reported that 54% of parents were unaware of the SDB and 84% did not know their complications. In the Northern Italy, the diagnosis was frequently performed with instrumental tools and the treatment was often surgical. In the Southern Italy the diagnosis was clinical, and the treatment was usually with drugs. CONCLUSIONS: The results of our study showed a heterogeneity in the diagnosis and treatment of SDB throughout Italy. Parents know little about SDB and their complications. The operator satisfaction was associated with the availability of tools for diagnosing SDB.

Alcohol hangover induces mitochondrial dysfunction and free radical production in mouse cerebellum.

Alcohol hangover (AH) is defined as the temporary state after alcohol binge-like drinking, starting when ethanol (EtOH) is absent in plasma. Previous data indicate that AH induces mitochondrial dysfunction and free radical production in mouse brain cortex. The aim of this work was to study mitochondrial function and reactive oxygen species production in mouse cerebellum at the onset of AH. Male mice received a single i.p. injection of EtOH (3.8g/kg BW) or saline solution. Mitochondrial function was evaluated 6h after injection (AH onset). At the onset of AH, malate-glutamate and succinate-supported state 4 oxygen uptake was 2.3 and 1.9-fold increased leading to a reduction in respiratory control of 55% and 48% respectively, as compared with controls. Decreases of 38% and 16% were found in Complex I-III and IV activities. Complex II-III activity was not affected by AH. Mitochondrial membrane potential and mitochondrial permeability changes were evaluated by flow cytometry. Mitochondrial membrane potential and permeability were decreased by AH in cerebellum mitochondria. Together with this, AH induced a 25% increase in superoxide anion and a 92% increase in hydrogen peroxide production in cerebellum mitochondria. Related to nitric oxide (NO) metabolism, neuronal nitric oxide synthase (nNOS) protein expression was 52% decreased by the hangover condition compared with control group. No differences were found in cerebellum NO production between control and treated mice. The present work demonstrates that the physiopathological state of AH involves mitochondrial dysfunction in mouse cerebellum showing the long-lasting effects of acute EtOH exposure in the central nervous system.

Respiratory failure due to upper airway obstruction in children: use of the helmet as bridge interface.

Upper airway obstruction (UAO) can cause severe respiratory distress in young children by increasing inspiratory muscle load and decreasing alveolar ventilation, ultimately resulting in hypercapnia and hypoxemia which have long term negative cardiovascular effects. Although non-invasive continuous positive airway pressure (CPAP) improves gas exchange in these patients, use of conventional interfaces (nasal mask, nasal pillow and facial mask) may cause significant discomfort and lead to CPAP intolerance. We report five cases of children affected by UAO who experienced CPAP intolerance via application of conventional interfaces. Alternatively, we acutely applied helmet-CPAP which resulted in improved breathing pattern and gas exchange. Thereafter, patients received training with respect to a nasal CPAP interface, allowing successful long term treatment. In conclusion, these five clinical cases demonstrate that helmet-CPAP can be used acutely in children with UAO if compliance to conventional modalities is problematic, allowing for sufficient time to achieve compliance to nasal-CPAP.

GABA release from suprachiasmatic nucleus terminals is necessary for the light-induced inhibition of nocturnal melatonin release in the rat.

The daily rhythm of melatonin production in the mammalian pineal is driven by the endogenous circadian pacemaker in the suprachiasmatic nuclei. The major release period of melatonin is closely linked to the dark phase of the 24-h day/night cycle. Environmental light will affect melatonin release in two ways: (i) it entrains the rhythm of the circadian oscillator; and (ii) it causes an acute suppression of nocturnal melatonin release. These two effects of light are both mediated by the suprachiasmatic nucleus and enable the pineal gland to convey information about day length to the reproductive system through changes in melatonin levels. Glutamate is currently believed to be the major transmitter in the retinal ganglion cell fibers reaching the suprachiasmatic nucleus. At present no information is available, however, about the transmitter(s) implicated in the further propagation, i.e. from the suprachiasmatic nucleus onwards, of the light information. In the present study we provide evidence that the endogenous release of GABA from suprachiasmatic nucleus terminals is implicated in the further transmission of light information to the pineal gland. Bilateral administration of the GABA-antagonist bicuculline to hypothalamic target areas of the suprachiasmatic nucleus completely prevents the inhibitory effect of nocturnal light on melatonin secretion and the present study thus documents that retina-mediated photic activation of suprachiasmatic nucleus neurons induces the release of GABA from efferent suprachiasmatic nucleus nerve terminals, resulting in an inhibition of melatonin release by the pineal gland. Together with our previous (electro)physiological data these results identify GABA as an important mediator of rapid synaptic transmission of suprachiasmatic nucleus output to its target areas.

Aging-induced changes in 24-h rhythms of mitogenic responses, lymphocyte subset populations and neurotransmitter and amino acid content in rat submaxillary lymph nodes during Freund's adjuvant arthritis.

In young (two months) and aged (18 months) male rats injected s.c. with Freund's adjuvant or adjuvant's vehicle 18 days earlier, 24-h variations in mitogenic responses, lymphocyte subsets and monoamine and amino acid content were examined in submaxillary lymph nodes. Mitogenic responses to concanavalin A (Con A) and lipopolysaccharide (LPS) were higher during the light phase of daily photoperiod. Old rats exhibited a suppressed or impaired mitogenic response to Con A but not to LPS. Acrophases of 24-h rhythm in lymphocyte subset populations in submaxillary lymph nodes were: 18:37-19:44h (B cells), 09:00-10:08h (T and CD4(+) cells) and 12:19-15:58h (CD8(+) cells). Aging augmented B cells and decreased T, CD4(+) and CD8(+) cells. Significant correlations were found between Con A activity and T cells, between lymph node 5HT content and B, T and CD8(+) lymphocytes, and between lymph node 5HT and taurine and GABA content. Aging increased lymph node 5HT content but did not modify NE content. Lymph node concentration of aspartate, glutamate and taurine was higher at night while that of GABA attained peak values at late afternoon. Old rats injected with Freund's adjuvant showed a higher mean value (glutamate) and smaller amplitude (glutamate, taurine) than their respective young controls. The results further document the effects of aging on the chronobiology of the immune system.

Effect of melatonin treatment on 24-h variations in responses to mitogens and lymphocyte subset populations in rat submaxillary lymph nodes.

Wistar male rats were injected s.c. with melatonin (30 microg) or vehicle, 1 h before lights off, for 11 days. Ten days after beginning melatonin treatment, rats received Freund's complete adjuvant or its vehicle s.c., and after 2 days, they were sacrificed at six different time intervals throughout a 24-h cycle. The mitogenic effect of lipopolysaccharide (LPS) and concanavalin A (Con A), the activity of ornithine decarboxylase (ODC) and the relative size of lymphocyte subset populations were measured in submaxillary lymph nodes. In control rats, the mitogenic effects of LPS and Con A and ODC activity peaked during the afternoon. Injection of Freund's adjuvant induced a 10-h shift in the diurnal rhythm of the mitogenic effect of LPS to attain maximal values at night. Melatonin pretreatment blunted the daily variations in the mitogenic activity of Con A or LPS and, when given to Freund's adjuvant-injected rats, augmented mesor and amplitude of diurnal rhythm in ODC activity. Maxima in B cell number occurred at night whereas those of T and B-T cell number occurred during the afternoon. During the early phase of immunization tested, the number of B cells augmented and the amplitude of its diurnal rhythmicity increased both after immunization and following melatonin pretreatment. Maxima of 24-h rhythms in CD4+ and CD4+/CD8+ cell populations occurred during the afternoon while those of CD8+ cells occurred at late night. Melatonin significantly augmented CD4+ cell number and decreased CD8+ cell number; it therefore augmented the CD4+:CD8+ ratio. The results suggest that pretreatment with a pharmacological dose of melatonin exerts immunomodulating effects at an early, preclinical, phase of Freund's adjuvant-induced arthritis in rats.

Effect of superior cervical ganglionectomy on 24-h variations in hormone secretion from the anterior hypophysis and in hypothalamic monoamine turnover during the preclinical phase of Freund's adjuvant arthritis in rats.

The effect of superior cervical ganglionectomy (SCGx) on 24-h rhythms of circulating adrenocorticotropic hormone (ACTH), growth hormone (GH), prolactin and luteinizing hormone (LH) and of hypothalamic noradrenaline content and dopamine and serotonin turnover, was assessed in rats 3 days after administering Freund's complete adjuvant. In sham-operated rats, Freund's adjuvant injection increased serum ACTH without affecting its diurnal rhythmicity. SCGx, performed 10 days earlier, suppressed 24-h rhythmicity and augmented mean values of circulating ACTH. A depressive effect of immunization on GH release was found in both sham-operated and SCGx rats. GH concentrations did not exhibit diurnal rhythmicity and decreased after immunization. Time-of-day-related changes in serum prolactin were significant for all examined groups, except for SCGx-immunized rats. Freund's adjuvant administration augmented prolactin secretion. Daily changes in serum LH concentration and a decrease after immunization were found in both sham-operated and SCGx rats. SCGx: (i) counteracted inhibition of daily variations of noradrenaline content in medial hypothalamus of Freund's adjuvant-injected rats; (ii) decreased anterior hypothalamic dopamine turnover and augmented it in the medial hypothalamus; (iii) lowered amplitude of serotonin turnover rhythm in medial hypothalamus. The data indicate that several early changes in levels and 24-h rhythms of circulating ACTH and prolactin, and in hypothalamic noradrenaline content and dopamine and serotonin turnover, were modified by a previous SCGx in Freund's adjuvant-injected rats.

Evidence for local synthesis of melatonin in golden hamster retina.

Daily variations in melatonin content of retinas of pinealectomized and sham-operated golden hamsters were studied. Melatonin content showed significant daily variations with maximal values at night (i.e. early in the night in pinealectomized hamsters and late at night in sham-operated animals). Moreover, mean retinal melatonin levels augmented significantly after pinealectomy. In vitro the augmented melatonin levels found in retinas incubated in darkness for 8 h was suppressed by exposure to light, indicating the ability of hamster retina to regulate melatonin synthesis in isolated conditions. Taken together, the in vivo and in vitro results support daily variations of melatonin content of exclusive retinal origin.

Specific destruction of the serotonergic afferents to the suprachiasmatic nuclei prevents triazolam-induced phase advances of hamster activity rhythms.

Administration of Triazolam (Tz)--a short acting benzodiazepine (BZ)--induces permanent phase-shifts in locomotor activity of golden hamsters (Mesocricetus auratus). However, the target area(s) as well as the mechanism involved in the Tz-induced changes are not known. Previous results indicated that raphe nuclei (RN) would appear to be a likely site for Tz-induced phase shifts. Therefore, we specifically destroyed the 5-HT fibers connecting the RN with the SCN--the site of the endogenous mammalian clock--by microinjections of the selective neurotoxin 5,7 dihydroxytryptamine (5,7-DHT) at the level of SCN. Infusion of 5,7-DHT resulted in long lasting damage of the ascending serotonergic projection from RN to the hypothalamus. Subsequently, the phase-shifting effect of Tz was investigated. Only complete or almost complete depletion of the 5-HT input to the SCN was accompanied with a pronounced reduction of the phase shift together with a significant reduction of wheel-running activity during the 6 h following Tz injection. Our present results support the view that the 5-HT innervation of the SCN represents an essential link in the phase-shifting action following peripheral Tz injections.

No triazolam-induced expression of Fos protein in raphe nuclei of the male Syrian hamster.

While the visual projections to the suprachiasmatic nuclei (SCN) play a role in mediating the effects of light on circadian rhythms, the functional significance of the serotonergic projection from the raphe nuclei (RN) to the SCN is uncertain. Because previous results indicated that RN would appear to be a likely site for triazolam (Tz)-induced phase shifts, we used the expression of Fos-protein as a marker of Tz-induced neuronal activation. Immunocytochemistry was used to visualize the presence of Fos-like protein. Tz-induced Fos-labeled nuclei were found in superior colliculi, Edinger-Westphal nuclei (EW) and dorsal tegmental nuclei (DTg), but not in the RN. The SCN showed only occasionally labeled nuclei in all experimental groups, whereas there was no Tz-induced Fos-immunoreactivity in the intergeniculate leaflet (IGL). The present data not necessarily exclude the implication of the RN in the phase shifting effect of Tz. The phase shift could still be accomplished using a different set of immediate early genes (IEG), or without an IEG response. Alternatively, as will be discussed, other pathways could mediate the phase shifting effect of Tz.