Umit Sehirli

GABAA receptor mediated transmission in the thalamic reticular nucleus of rats with genetic absence epilepsy shows regional differences: Functional implications

The aim of the present study was to investigate the effect of local injections of the GABA(A) receptor antagonist, bicuculline, into the rostral and caudal parts of the thalamic reticular nucleus (TRN), on the generation of spike-and-wave discharges in Genetic Absence Epilepsy Rats from Strasbourg (GAERS). Spike-and-wave discharges are important in the pathophysiology of absence epilepsy and generated by the cortico-thalamo-cortical pathway, where GABA has a significant role, particularly in the TRN. Artificial cerebrospinal fluid or bicuculline was administered to rostral or caudal parts of TRN of GAERS through a stereotaxically placed guide cannula. Administration of bicuculline produced opposite effects according to the injection site. Administration into the caudal TRN produced statistically significant increases in the duration of spike-and-wave discharges, whereas injections into the rostral TRN produced significant decreases. Correspondingly, distinct patterns of afferent connections have been demonstrated with the wheat-germ-agglutinin horseradish peroxidase (WGA-HRP) retrograde tracing method in control non-epileptic rats and GAERS for the rostral and caudal parts of the TRN. Injection of WGA-HRP tracer showed no detectable difference regarding the rostral and caudal connections between GAERS and Wistar animals. Rostral parts of TRN have thalamic and cortical connections that are primarily motor and limbic whereas for the caudal parts these connections are primarily sensory. Further, the rostral parts receive inputs from the substantia nigra pars reticularis and the ventral pallidum that the caudal part lacks. The extent to which these connectional differences may be responsible for the functional differences demonstrated by the bicucculine injections remains to be explored.

Topical glucocorticoid reduces the topical decongestant–induced histologic changes in an animal model nasal mucosa

To investigate the histologic consequences of simultaneous nasal glucocorticosteroid and xylometazoline HCl administration in the rabbit nasal mucosa.

Dopamine acting at D1-like, D2-like and α1-adrenergic receptors differentially modulates theta and gamma oscillatory activity in primary motor cortex

The loss of dopamine (DA) in Parkinson’s is accompanied by the emergence of exaggerated theta and beta frequency neuronal oscillatory activity in the primary motor cortex (M1) and basal ganglia. DA replacement therapy or deep brain stimulation reduces the power of these oscillations and this is coincident with an improvement in motor performance implying a causal relationship. Here we provide in vitro evidence for the differential modulation of theta and gamma activity in M1 by DA acting at receptors exhibiting conventional and non-conventional DA pharmacology. Recording local field potentials in deep layer V of rat M1, co-application of carbachol (CCh, 5 μM) and kainic acid (KA, 150 nM) elicited simultaneous oscillations at a frequency of 6.49 ± 0.18 Hz (theta, n = 84) and 34.97 ± 0.39 Hz (gamma, n = 84). Bath application of DA resulted in a decrease in gamma power with no change in theta power. However, application of either the D1-like receptor agonist SKF38393 or the D2-like agonist quinpirole increased the power of both theta and gamma suggesting that the DA-mediated inhibition of oscillatory power is by action at other sites other than classical DA receptors. Application of amphetamine, which promotes endogenous amine neurotransmitter release, or the adrenergic α1-selective agonist phenylephrine mimicked the action of DA and reduced gamma power, a result unaffected by prior co-application of D1 and D2 receptor antagonists SCH23390 and sulpiride. Finally, application of the α1-adrenergic receptor antagonist prazosin blocked the action of DA on gamma power suggestive of interaction between α1 and DA receptors. These results show that DA mediates complex actions acting at dopamine D1-like and D2-like receptors, α1 adrenergic receptors and possibly DA/α1 heteromultimeric receptors to differentially modulate theta and gamma activity in M1.

Early Onset of Atherosclerosis of The Carotid Bifurcation in Newborn Cadavers.

INTRODUCTION The anatomy of arterial bifurcations affects blood flow and has a significant role in the development of vascular disease. Therefore, it is important to know the structural characteristics of the Common Carotid Artery (CCA) and its branches for early onset of atherosclerosis in newborns. AIM The present study was conducted to evaluate the characteristics of CCA in newborn cadavers. MATERIALS AND METHODS Eight carotid arteries obtained from newborn cadavers were used. The outflow to inflow area ratios was calculated to evaluate vessel diameters. Additionally, scanning electron and light microscopic investigations were conducted with tissue samples. The brachial artery of each cadaver was used as controls. Correlation between area ratios and atherosclerotic endothelial damage was determined. RESULTS Light microscopic investigations demonstrated that control group sections showed no positivity for Oil red O staining, while carotid bifurcation regions depicted widespread occurrence of intimal lipid accumulations. Scanning electron microscopic examination of control group sections presented regular endothelial topography, while carotid bifurcation region topography exhibited numerous blood cells and separated endothelial cells. Fibrin accumulation on endothelial surface in low area ratios was another important finding in the examination of its endothelial surface degeneration. The above-mentioned morphological findings seemed to be quite parallel to outflow to inflow area ratio data favouring low area and degeneration. CONCLUSION The correlation between area ratios and the histological characteristic of cerebral vessels of newborn cadavers indicate that early stages of atherosclerosis began in early embryologic life.

Prelimbic Cortex Deep Brain Stimulation Reduces Binge Size in a Chronic Binge Eating Rat Model

Background: Binge eating (BE) involves the consumption of a large amount of food in a short period of time and a loss of control during the binge episode. It is a key feature of the major subtypes of eating disorders like bulimia nervosa, BE disorder, anorexia nervosa binge/purge type. Alterations in the mesocorticolimbic pathway play a crucial role in its pathophysiology. Objectives: We hypothesized that BE rats receiving deep brain stimulation (DBS) in the prelimbic cortex, a functional analog of the dorsolateral prefrontal cortex in humans, would have a reduced binge size compared with those receiving sham stimulation. Methods: Eight male Sprague-Dawley rats were implanted with a DBS electrode in the left prelimbic cortex. A protocol which included limited access to a “sweet-fat” diet was used to achieve a chronic BE state in the rats. After reaching a stable binge size, each rat had undergone sham, low-frequency stimulation (60 Hz), and high-frequency (130 Hz) stimulation for 3 sessions each, and 2 consecutive treatments were separated by at least 2 empty sessions to allow a washout of the effects. A one-way ANOVA was used for the data analysis. Results: Low-frequency (60 Hz) stimulation of the prelimbic cortex significantly reduced the binge size compared to the sham stimulation (p < 0.0001). High-frequency DBS (130 Hz) had no significant influence on this behavior when compared to sham stimulation (p = 0.9). Conclusions: This study suggests that low-frequency prelimbic cortex stimulation in BE would be useful for correcting prefrontal hypofunction which is strongly associated with BE and addiction pathogenesis.

Diagnostic utilities of tracheal ultrasound and USB-endoscope for the confirmation of endotracheal tube placement: A cadaver study

Objectives: Confirmation of the endotracheal tube placement (CoETP) has the utmost importance in the management of an airway. Visualization of tracheal rings or carina with a fiber‐optical bronchoscope (FOB) has considered to be a reliable method for the CoETP. However, FOB is expensive, time‐consuming, and not always practical. Inexpensive endoscopic USB‐cameras were shown to aid intubation successfully and reliably. On the other hand, there have been no studies investigating their use for the CoETP. Tracheal ultrasonography (TUS) is also a new, inexpensive and widely available alternative. A cadaver study has planned to evaluate the diagnostic utility of TUS and a USB‐camera. Methods: This study was conducted in the Anatomy Lab of a University on a fresh frozen female cadaver. Three senior Emergency Physicians have intubated the cadaver, and performed TUS or USB‐endoscopy. We have prepared a randomized intubation list (n = 96) in three blocks (3 times 32) as to include equal number of esophageal and tracheal intubations (48 for each). Each EP is performed all three interventions (intubation, TUS and USB‐endoscopy) in consecutive blocks of 32 intubations, in turn. The position of the tube has been verified from a 2 cm wide ostium on the proximal trachea. Results: In this study, all intubations (n = 96, 100%) were correctly identified as tracheal or esophageal with both TUS and USB‐camera. Both the sensitivity and specificity of TUS and USB‐endoscopy for the CoETP were 100.0%. Conclusion: The perfect accuracy of TUS and USB‐endoscopy, have placed those techniques in a unique position as an alternative in resource‐poor situations.