Afsaneh Zargarani

Introduction: The early ventricular system with it's architecture surrounding midline structures and expansion to the brain cortex, and fluid flow plays dramatically a great role in the development of the central nervous system The cerebrospinal fluid contains distinct concentrations of variety of motogenes, mitogens, morphogenes, and many other essential growth factors and neurotrophines that are effectively programming the neural cell fates and thus brain architecture. SLIT2 a member of SLIT family of chemorepellents is famous for it's role in midline crossing during axonal growth and arborization. Aim: Previous studies indicated the presence of SLIT2 mRNA in the neural cells and Choroid plexus during development. In the present study the presence of SLIT2 protein in the cerebrospinal fluid of the fourth ventricle of the brain is investigated and whether there is any perceivable fluctuations in the concentration of this protein. Materials & Methods: Based on ethics, over 1000 rat fetuses during embryonic days 16-­‐20 were applied to cerebrospinal fluid extraction from the cisterna magna region of the brain with glassy micropipettes. The pure cerebrospinal fluid specimens subsequently were centrifuged (1500 rpm for 3-­‐5 min) and stored in-­‐80 degree Celsius for 2-­‐3 months. The sandwich ELISA protein assay was applied respectively for both technical and experimental repeats. The repeats were 3-­‐8 times according to the restrictions of specimen's volume which were due to fetal sizes. Results: The ELISA assay indicated that there are noticeable concentrations of SLIT2 during Embryonic days 16, 17, and 20. Besides there are countable concentrations of SLIT2 during embryonic days 18, and 19. There was a rise from E16 to E17, almost the concentration was doubled. From E17 to E18 there was a dramatic fall, so close to unmeasurable amount. A gradual rise from E18 to E19 was observed. From E19 to E20 a sharp rise almost at the same concentration of E17 was perceived. Conclusions: The ELISA assay clearly revealed the presence of SLIT2 protein in the cerebrospinal fluid of the fourth ventricle of the brain during embryonic days 16-­‐ 20 of fetal development. Furthermore, there were obviously perceivable fluctuations in the concentrations measured during this assay both in experimental and technical assays that suggest there should be a pattern of

Organizing a great deal of trajectories spanning the whole central nervous system (CNS), orexinergic system is involved in numerous functional and cognitive criteria of CNS’s vital activities and responds including nociception. Previous investigations demonstrated Orexin-1 and -2 receptors (OX1R and OX2R) are playing a modulatory role in anti-nociceptive mechanisms. Highly densified distribution of orexinergic neurons in the lateral hypothalamus (LH) and their projections to Cornu Ammonnic 1 (CA1) region of the hippocampus, where their receptors are massively available, give rise to a query whether antagonizing CA1-OX1R and -OX2R could modulate the anti-allodynic behavior chemically induced by agonizing cholinergic neurons in LH. The present study is designed to investigate this inquiry on animal models by means of applying thermal acute pain via tail-flick test. It was apparently documented that following the inhibition of both receptors, antinociception state induced by LH stimulation was attenuated, although the two receptors depicted distinct manners in pain-modulation.

The lateral hypothalamus (LH) orexinergic neurons project to numerous brain regions implicated in pain perception, including the CA1 part of the hippocampal formation. Moreover, the roles of orexin receptors (OXRs) in the CA1 in anti-analgesic consequences of the LH chemical stimulation by carbachol, muscarinic receptor agonist, in acute pain have not been clarified. The current research showed OXRs antagonist administration's effect in the CA1 on analgesia elicited by the LH chemical stimulation in a tail-flick test as an acute model of pain. The control groups, including vehicle-control groups, were given intra-LH administration of saline (0.5 µl), following intra-CA1 infusion of DMSO (12%; 0.5 µl), and carbachol-control groups were treated with carbachol (250 nM/0.5 µl saline) into the LH following DMSO in the CA1. Treated groups received SB334867 (1, 3, 10, and 30 nM/0.5 µl DMSO) or TCS OX2 29 (0.1, 1, 10, and 20 nM/0.5 µl DMSO) as OX1R or OX2R antagonist, respectively, in the CA1 prior intra-LH administration of carbachol. After all injections, all rats underwent the tail-flick test over a 60-min time. Infusion of SB334867 or TCS OX2 29 in the CA1 impaired the analgesic consequences following chemical stimulation of the LH in acute pain. Meanwhile suppressive impact of the OX1R or OX2R antagonist on the analgesic impact of LH chemical stimulation was approximately identical. The current investigation provided a new document about the critical involvement of hippocampal orexinergic system in the modulatory role of the LH-CA1 path in pain perception.

The lateral hypothalamus (LH) orexinergic neurons project to numerous brain regions implicated in pain perception, including the CA1 part of the hippocampal formation. Moreover, the roles of orexin receptors (OXRs) in the CA1 in anti-analgesic consequences of the LH chemical stimulation by carbachol, muscarinic receptor agonist, in acute pain have not been clarified. The current research showed OXRs antagonist administration's effect in the CA1 on analgesia elicited by the LH chemical stimulation in a tail-flick test as an acute model of pain. The control groups, including vehicle-control groups, were given intra-LH administration of saline (0.5 μL), following intra-CA1 infusion of DMSO (12 %; 0.5 μL), and carbachol-control groups were treated with carbachol (250 nM/0.5 μL saline) into the LH following DMSO in the CA1. Treated groups received SB334867 (1, 3, 10, and 30 nM/0.5 μL DMSO) or TCS OX2 29 (0.1, 1, 10, and 20 nM/0.5 μL DMSO) as OX1R or OX2R antagonist, respectively, in the CA1 prior intra-LH administration of carbachol. After all injections, all rats underwent the tail-flick test over a 60min time. Infusion of SB334867 or TCS OX2 29 in the CA1 impaired the analgesic consequences following chemical stimulation of the LH in acute pain. Meanwhile suppressive impact of the OX1R or OX2R antagonist on the analgesic impact of LH chemical stimulation was approximately identical. The current investigation provided a new document about the critical involvement of hippocampal orexinergic system in the modulatory role of the LH-CA1 path in pain perception.