The piriform cortex (PCx) receives direct input from the olfactory bulb (OB) and is the brain's main station for odor recognition and memory. The transformation of the odor code from OB to PCx is profound: mitral and tufted cells in olfactory glomeruli respond to individual odorant molecules, whereas pyramidal neurons (PNs) in the PCx responds to multiple, apparently random combinations of activated glomeruli. How these ‘discontinuous’ receptive fields are formed from OB inputs remains unknown. Counter to the prevailing view that olfactory PNs sum their inputs passively, we show for the first time that NMDA spikes within individual dendrites can both amplify OB inputs and impose combination selectivity upon them, while their ability to compartmentalize voltage signals allows different dendrites to represent different odorant combinations. Thus, the 2-layer integrative behavior of olfactory PN dendrites provides a parsimonious account for the nonlinear remapping of the odor code from bulb to cortex.
The piriform cortex (PCx) is essential for learning of odor information. The current view postulates odor learning in the PCx is mainly due to plasticity in intracortical (IC) synapses, while odor information from the olfactory bulb carried via the lateral olfactory tract (LOT) is 'hardwired'. Here we revisit this notion by studying location and pathway dependent plasticity rules. We find that in contrast to the prevailing view, synaptic and optogenetically activated LOT synapses undergo strong and robust long-term potentiation (LTP) mediated by only few local NMDA-spikes delivered at theta frequency, while global spike timing dependent plasticity protocols (STDP) failed to induce LTP in these distal synapses. In contrast, IC synapses in apical and basal dendrites undergo plasticity with both NMDA-spikes and STDP protocols but to a smaller extent compared with LOT synapses. These results are consistent with a self-potentiating mechanism of odor information via NMDA-spikes which can form branch-specific memory traces of odors that can further associate with contextual IC information via STDP mechanisms to provide cognitive and emotional value to odors.
Background:The lack of vaccines and limitations of currently available strategies demand a need to develop safe and efficacious immunomodulators. Phyllostachys bambusoides is traditionally used for various autoimmune and infectious disorders, a property possibly attributable to presence of flavonoids like orientin and iso-orientin. Objective: the objective of this study was, to search a potent immunomodulator which elicit both Th1 and Th2 immune response. Methods: The animals were (Balb/c) treated with the bioactive fraction (PBC) from P. bambusoides (100 and 200 mg/kg body weight) for 14 days with SRBC (Sheep Red Blood Cells) as an antigen. Haemagglutination antibody (HA) titre, delayed type hypersensitivity (DTH) reaction, phagocytic index, NO production, analysis of cytokines in serum and CD80/ CD86 population in spleen. Results: PBC significantly enhanced the expression of IgM and IgG titre and DTH response in a dose dependant manner after 24 and 48 h in BALB/c mice with a maximum response at 200 mg/Kg. Besides humoral and cell mediated immunity, it also enhanced phagocytic index, nitric oxide production, which further leads to protection against Candida albicans infection. It also, enhanced the expression of CD80 and CD86 in splenic cells. Conclusion: Taken together these in vitro and in vivo data, our results suggest that PBC acts as an effective immunostimulator which specially enhances macrophage function during infection. This further supports the role of PBC in immunopharmacologic applications.
Corroles,m acrocycles that owe their name to the cobalt-chelating prosthetic group of vitamin B12 and share numerous features with the iron-chelating porphyrin present in heme proteins/enzymes,c onstantly cross new boundaries ever since stable derivatives became easily accessible.P articularly important is the increasing utilization of corroles and the corresponding metal complexes for the benefit of mankind, in terms of new drug candidates for treating various diseases and as catalysts for sustainable energy relevant processes.O ne challenge is to gain access to the plain macrocycle,astoallow for full elucidation of the most fundamental properties of corroles.W eh ave obtained the substituent-free corrole by several surprising and conceptually different pathways. Selected features of the corresponding metal complexes are illuminated, for pointing towards unique phenomena that are anticipated to largely expand the horizonr egarding their utilization for contemporary catalysis.
Background: To compare propofol and etomidate as anaesthetic agents for elective non-cardiac surgery with respect to stability of haemodynamic parameters, systemic side effects and quality of induction.Methods: Randomised, blinded study of 100 patients posted for elective non-cardia surgery under general anaesthesia, divided in to two group. In group P(n=50) induction was achieved with injection Propofol 1mg/kg, whereas in group E(n=50), it was achieved with injection etomidate 0.3mg/kg after premedication with injection midazolam 0.04mg/kg and fentanyl 2µg/kg in both the group. Hemodynamic parameters like, heart rate, systolic BP, diastolic BP, Mean BP and induction time in seconds, pain on injection, myoclonus, post-operative nausea, vomiting were recorded at different time intervals (base line, at induction, immediately after intubation and 1,3,5 and 15 min after intubation).Results: There was no statistically difference was found in demographic profile and baseline hemodynamic parameters but significant different was found in intraoperative mean HR, SBP, DBP, MBP at various time intervals, and our result was more in favour of E group as compare to P, in which above recorded vital parameters were decreased more than E and induction time was also faster in E as compare to P. Pain on injection and post-operative nausea, vomiting was more in group P as compare to E, however the myoclonus movements was more in E group as compare to P but statistically not significant.Conclusions: Etomidate is a better intravenous induction agent of anaesthesia than Propofol in hemodynamically unstable patient also as it has faster onset of action with less pain and post-operative nausea, vomiting with good hemodynamic stability.
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