Browsing by Author "Chahl, LA"

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    Immunohistochemical localisation of the NK1 receptor in the human amygdala: Preliminary investigation in schizophrenia
    (Elsevier, 2006-09-30) Weidenhofer, J; Yip, J; Zavitsanou, K; Huang, XF; Chahl, LA; Tooney, PA
    The amygdala has a role in the modulation of moods and emotion, processes that are known to be affected in people wi th psychiatric disorders such as schizophrenia and depression. The tachykinin NK1 receptor is known to be expressed in the amygdala. However to date, there is limited knowledge of the distribution of the NK1 receptor in this region. This study used immunohistochemistry to analyse the distribution of the NK1 receptor in fixed human amygdala tissue in control subjects with no history of psychiatric illness and matched subjects with a diagnosis of schizophrenia (n = 4 pairs). The NK1 receptor was observed sparsely distributed in cell bodies in all amygdaloid nuclei with the basolateral and lateral having a greater relative density of NK1 receptor-immunoreactive cell bodies than the other nuclei. Double labelling with antibodies to microtubule associated protein and the NK1 receptor revealed that the NK1 receptor is expressed by large pyramidal, small stellate and large bipolar neurons. Interestingly, the basal nucleus of Meynert, which is just dorsal to the amygdala, was observed to have a significantly higher relative density of NK1 receptor-immunoreactive cell bodies compared to any of the amygdaloid nuclei. Preliminary analysis of the density of NK1 receptor-immunoreactive cell bodies in the major amygdaloid nuclei and the basal nucleus of Meynert revealed no significant differences between schizophrenia and control subjects. Real-time PCR showed that the mRNA for both the short and long isoforms of the NK1 receptor was expressed at low levels in fresh frozen human amygdala tissue from control subjects and that this was not different in matched subjects with schizophrenia (n = 11 pairs). In conclusion, this study has demonstrated that the NK1 receptor is widely distributed in the amygdala, and has shown for the first time a high relative density of NK1 receptor-immunoreactive cell bodies in the basal nucleus of Meynert. © 2006, Elsevier Ltd.
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    Receptor changes in brain tissue of rats treated as neonates with capsaicin
    (Elsevier, 2010-07) Zavitsanou, K; Dalton, VS; Wang, HQ; Newson, P; Chahl, LA
    Capsaicin, the hot chemical in chillies, administered to neonatal rats, causes destruction of polymodal nociceptive primary afferent neurons by acting on TRPV1 receptors causing intrinsic somatosensory deprivation. Although the effects of neonatal capsaicin treatment in the periphery have been extensively investigated, less is known about the brain networks to which the capsaicin sensory neurons are relayed. In the present study the effect of neonatal capsaicin treatment on brain receptors that have been shown to interact with TRPV1 was examined. Wistar rats were treated on neonatal day 2 with capsaicin and at 15–16 weeks of age, brains were processed to measure levels of muscarinic M1/M2 and M2/M4, serotonin 5HT2A, cannabinoid CB1, dopamine D1, D2 receptors and dopamine transporter. Overall increases in levels of muscarinic M1/M4 (F = 8.219, df = 1, p = 0.005), muscarinic M2/M4 (F = 99.759, df = 1, p < 0.0001), serotonin 5HT2A (F = 28.892, df = 1, p < 0.0001), dopamine D1 (F = 8.726, df = 1, p = 0.008) and cannabinoid CB1 (F = 25.084, df = 1, p < 0.0001) receptors were found in the brains of capsaicin-treated rats, although significant regional changes occurred only in muscarinic M2/M4 and serotonin 5HT2A receptors. The results of the present study suggest that neonatal intrinsic somatosensory deprivation may have a significant impact on substrates at the central nervous system that manifest as changes in central cholinergic, monaminergic and cannabinoid systems in the adult animal. © 2010, Elsevier Ltd.