Application Of KCl Research Articles

Eighteen-hour inhibitory effect of s-ketamine on potassium- and ischemia-induced spreading depolarizations in the gyrencephalic swine brain

Spreading depolarizations (SDs) are characterized by near-complete breakdown of the transmembrane ion gradients, cytotoxic edema, and glutamate release. SDs are associated with poor neurological outcomes in cerebrovascular diseases and brain trauma. Ketamine, a N-methyl-d-aspartate receptor antagonist, has shown to inhibit SDs in animal models and in humans. However, little is known about its SD-inhibitory effect during long-term administration.Lissencephalic animal models have shown that ketamine loses its SD-blocking effect after some minutes to hours. Physio-anatomical differences between lissencephalic and the more evolved gyrencephalic animals may affect their SDs-blocking effect. Therefore, information from the last may have more translational potential. Therefore, the aim of this study was to investigate the 18 h-effect of s-ketamine as a basis for its possible long-term clinical use for neuroprotection. For this purpose, two gyrencephalic swine brain models were used. In one, SDs were elicited through topical application of KCl; in the other model, SDs were spontaneously induced after occlusion of the middle cerebral artery. S-ketamine was administered at therapeutic human doses, 2, 4 and 5 mg/kg BW/h for up to 18 h. Our findings indicate that s-ketamine significantly reduces SD incidence and expansion without clear evidence of loss of its efficacy. Pharmacological susceptibility of SDs to s-ketamine in both the ischemic gyrencephalic brain and well-perfused brain was observed. SDs were most potently inhibited by s-ketamine doses that are above the clinically recommended (4 mg/kg BW/h and 5 mg/kg BW/h). Nonetheless, such doses are given by neurointensivists in individual cases. Our results give momentum to further investigate the feasibility of a multicenter, neuromonitoring-guided, proof-of-concept clinical trial.

Dynamic Measurements of Cerebral Blood Flow Responses to Cortical Spreading Depolarization in the Murine Endovascular Perforation Subarachnoid Hemorrhage Model.

Delayed cerebral ischemia (DCI) is the most severe complication after subarachnoid hemorrhage (SAH), and cortical spreading depolarization (CSD) is believed to play a vital role in it. However, the dynamic changes in cerebral blood flow (CBF) in response to CSD in typical SAH models have not been well investigated. Here, SAH was established in mice with endovascular perforation. Subsequently, the spontaneous CBF dropped instantly and then returned to baseline rapidly. After KCl application to the cortex, subsequent hypoperfusion waves occurred across the groups, while a lower average perfusion level was found in the SAH groups (days 1-7). Moreover, in the SAH groups, the number of CSD decreased within day 7, and the duration and spreading velocity of the CSD increased within day 3 and day 14, respectively. Next, we continuously monitored the local field potential (LFP) in the prefrontal cortex. The results showed that the decrease in the percentage of gamma oscillations lasted throughout the whole process in the SAH group. In the chronic phase after SAH, we found that the mice still had cognitive deficits but experienced no obvious tissue damage. In summary, SAH negatively affects the CBF responses to CSD and the spontaneous LFP activity and causes long-term cognitive deficits in mice. Based on these findings, in the specific phase after SAH, DCI is induced or exacerbated more easily by potential causers of CSD in clinical practice (edema, erythrocytolysis, inflammation), which may lead to neurological deterioration.

328 Induced Spreading Depolarizations Produce Exaggerated Electrophysiologic Pathology in a Rat Model of Traumatic Brain Injury

INTRODUCTION: Spreading depolarizations (SDs) are waves of cortical depolarization that cause loss of ion homeostasis, brain silencing, and are prognostic of worse functional outcome in traumatic brain injury (TBI) patients. SDs occur in ∼50% of surgical TBI patients and have potential to spread from areas of injured brain into less-injured or “uninjured” cortex. Understanding differences in how injured versus uninjured cortex responds to SD waves can provide insight for therapeutic targets. METHODS: Adult Long Evans rats were subjected to either a moderate lateral fluid percussion injury (LFPI) or a sham injury. Beginning 103.4 ± 28.4 minutes after injury or sham, an electrode was placed at the site of injury (or sham) and electrocorticographic activity was recorded for two hours. SDs were induced every 15 minutes using 1M potassium chloride (KCl) soaked cotton balls placed on a frontal craniectomy separate from the recording site. Saline soaked cotton balls were used as a control. RESULTS: A total of 37 SDs were induced in the uninjured group and 32 SDs were induced in the injured group. No SDs were recorded in saline controls. There was no difference in the average time from KCl application to the start of the SD between groups (sham = 136.2, LFPI = 113.9, p = 0.4219). There was also no difference in average amplitude of the direct current (DC) shift (sham = 10.33, LFPI = 13.26, p = 0.1402). However, the injured group had longer average duration of DC shifts (sham = 53.54, LFPI = 99.22, p < 0.0001), longer average depression durations (sham = 206.6, LFPI = 265.8, p = 0.001), and larger average depth of depression (sham = 0.6824, LFPI = 0.8399, p = 0.0018). CONCLUSION: Our study revealed electrophysiologic differences between SDs induced in injured versus uninjured animals. Further studies are needed to determine the impact of these differences on neuronal damage and functional outcome.

Timing of potassium chloride application effect on soil and potato uptake of chloride

AbstractPotassium chloride (KCl) is often used to supply K for potato (Solanum tuberosum L.) production; it is the least costly K fertilizer. However, crop uptake of Cl can reduce diagnostic petiole NO3–N and reduce tuber specific gravity. This trial evaluated the effect of K fertilizer source (KCl vs. sulfate of potash [SOP] and sulfate of potash magnesia [KMag]) and fertilizer application timing on Cl, S, N, and K in soil, petioles, and whole plant biomass. Fertilizers were applied at 224 kg K2O ha–1 at three application timings: 210 d before planting (fall preplant), 14 d before planting (spring preplant), or 35 d after planting (Layby) to a sandy loam soil in Hermiston, OR. Nitrogen fertilizer was applied by overhead sprinklers during the growing season. Potassium source and timing had minimal effect on crop S, N, and K uptake. Crop Cl response reflected a fertilizer source × timing interaction. Fall‐applied KCl did not increase plant Cl above that observed for KMag and SOP treatments. Spring or summer‐applied KCl increased plant Cl concentrations. The most likely explanation for this response pattern was leaching of Cl below rooting depth with fall fertilizer application. Findings of importance for potato production practices in our region included: (a) fall‐applied Cl was not taken up by the crop, and so did not represent a risk to potato tuber quality; (b) elevated concentrations of petiole Cl from preplant or in‐season KCl application did not affect petiole NO3–N.

Abnormal glutamatergic neurotransmission and cognitive impairment in male APPNL-F/NL-F mice.

It is well established that glutamatergic neurotransmission plays an essential role in learning and memory. In Alzheimer's disease (AD), previous studies indicate that glutamate dynamics shift with disease progression, inciting cognitive impairment and further perpetuating disease pathology. Here, we build upon previous work by utilizing a novel knock-in mouse model of AD (APPNL-F/NL-F ) to characterize hippocampal glutamate signaling and cognition during late stage AD. At 18-24 months old, male APPNL-F/NL-F and genetic background control (C57BL/6) mice underwent cognitive assessment through a Morris water maze (MWM) task. Following MWM, basal and 70 mM KCl stimulus-evoked glutamate release was measured in the CA1 region of the hippocampus using a glutamate-selective microelectrode in isoflurane anesthetized mice. Briefly, microelectrodes were coated with L-glutamate oxidase for the detection of glutamate at the electrode surface. A layer of 1,3-phenylenediamine was applied to prevent detection of electroactive compounds at the recording potential (+0.7 volts). A micropipette (diameter = ∼20 µm) was attached 50-100 µm from the recording surface for local application of KCl). Calibration and recordings are taken using the FAST-16 recording software. Preliminary MWM data indicates no significant differences in spatial learning performance (corrected integrated path length and cumulative distance from the platform) between C57BL/6 and APPNL-F/NL-F mice. We observed a trend of decreased platform entries during the probe trial, supporting long-term spatial memory impairment in APPNL-F/NL-F mice. Preliminary in vivo CA1 data support a trend of decreased basal and stimulus-evoked glutamate levels in APPNL-F/NL-F mice compared to control mice. Preliminary findings support impaired long-term spatial memory and hypoactive glutamatergic neurotransmission in aged male APPNL-F/NL-F mice compared to age-matched C57BL/6 mice. Lack of glutamate activity in late-stage AD may underlie cognitive decline in APPNL-F/NL-F mice. Our laboratory previously observed similar findings in a transgenic AD model. However, unlike APPNL-F/NL-F mice, those mice also displayed increased basal glutamate levels. This divergence could be attributed to possible differences in glutamate transporter expression or activity with disease progression. Together, these data support loss of glutamate excitation with amyloid accumulation. Studies are ongoing.

Fertilization management strategies for ‘Agata’ potato production

ABSTRACT Fluctuations in potato prices and invariably rising production costs need sustainable fertilization strategies. For this purpose, two experiments were conducted in the southwestern region of São Paulo state to evaluate fertilization management strategies for the ‘Agata’ potato cultivar. The treatments consisted of the producer’s standard fertilization (1700 kg ha-1 NPK 4-30-10 at planting + 100 kg ha-1 urea and 150 kg ha-1 KCl at hilling) and combinations of two P rates at planting (standard rate and half of the rate), as monoammonium phosphate (MAP) with two forms of KCl application (total rate in the post-planting phase or half of the rate in the post-planting phase and half at hilling). The application of half the P rate (255 kg ha-1 P2O5) as the MAP at planting and the transfer of K from planting to applications in the post-planting phase or in the post-planting phase and at hilling, despite having provided a lower leaf P concentration, maintained the total tuber yield with higher operational yield of planting fertilization. It also increased the yield of tubers with a diameter >4.5 cm under conditions of lower water availability in the vegetative stages of the crop and soil with medium availability of P and K. Such a fertilization strategy is valuable for cost reductions and possible environmental liabilities.

Interactive effect of irrigation and blend ratio of controlled release potassium chloride and potassium chloride on greenhouse tomato production in the Yellow River Basin of China

Soil water and fertilizer are two main factors affecting tomato yield and quality, and their optimization management is crucial for sustainable production. There are many studies about the response of tomato growth and fruit yield formation to irrigation level and potassium (K) fertilizer, but few studies have been conducted on the responses of irrigation level and controlled release potassium chloride (CRK), not to mention the different irrigation levels and CRK to KCl blending ratios. In this study, two consecutive growing seasons (2020–2021) tomato pot experiments were presented with three irrigation levels (W100, W80, and W60) and three blending ratios of CRK to KCl (100%, 80%/20%, 60%/40%) under the condition that the amount of potassium fertilizer was reduced by 40% compared with conventional application rate. The results revealed that under W80 water conditions, 80% CRK mixed with 20% KCl application led to a significant increase in tomato yield by 4.1–11.9% and 4.6–18.9%, K use efficiency by 11.5–34.2% and 6.1–32.3%, fruit vitamin C content by 9.3–25.3% and 5.6–28.3%, fruit soluble sugar content by 10.2–20.0% and 10.2–24.1% in 2020 and 2021, respectively, compared with the other K fertilization treatments. Meanwhile, the water use efficiency and fruit soluble solid content of W80K80 treatment were also maintained at a high level. Molecular analysis shows that the W80K80 treatment had a higher photosynthetic rate, rubisco content, cytokinin content, and osmotic regulation substances content, and lower abscisic acid (ABA), malondialdehyde (MDA), and hydrogen peroxide (H2O2) contents. Our results indicated that 80% irrigation level and 80% CRK-20% KCl blending ratio were the optimal water and K supply mode for tomato production in this study. The result provided useful information regarding greenhouse tomato production that would allow the achievement of higher fruit yield, quality and resource use efficiencies, and provided theoretical and technical support for greenhouse tomato irrigation and K fertilizer application technologies.

An investigation of the effects of synthesized zinc oxide nanoparticles on the properties of water-based drilling fluid

The deterioration of drilling fluid properties during deep drilling causes problems like inefficient cutting removal, fluid invasion, and shale swelling, which increases non-productive time (NPT) and cost. Recently nanoparticles (NPs) based drilling fluid are introduced to address these impediments since these particles prove their advantages in different stages of petroleum exploration and recovery. Previous developments are concerned with the use of commercial zinc oxide (ZnO) NPs in inorganic KCl salt-based drilling fluid, although application of KCl in drilling fluid arouses environmental complications. In this study, ZnO NPs prepared in the laboratory are used in water-based drilling fluid (WBDF) to assess the effect of nanoparticles on the properties of drilling fluid at two temperature conditions of 40 °C and 80 °C. A base mud is formulated, and ZnO NPs with five different concentrations of 0.05, 0.1, 0.5, 1.0, and 2.0 wt% are mixed with the base mud. The experimental analysis shows that NPs improve the rheological properties of WBDF. When the concentration of NPs was 0.1 wt%, the yield point increased by 61.54% at 40 °C, and when the concentration of NPs was 0.05 wt%, the yield point increased by 60% at 80 °C. Besides, when the concentration of NPs is 0.05 wt%, 10-sec gel strengths are enhanced by 25% and 50% at 40 °C and 80 °C, respectively. The API low-pressure low-temperature (LPLT) filter volume is not significantly affected by the addition of NPs in WBDF. However, mud cake thickness continuously reduces with the increase of NPs concentrations. This result reveals that a superior rheological improvement is achieved at low NPs concentration (0.05 wt%) at higher temperature.

Widespread brain parenchymal HMGB1 and NF-κB neuroinflammatory responses upon cortical spreading depolarization in familial hemiplegic migraine type 1 mice

Neuroinflammatory changes involving neuronal HMGB1 release and astrocytic NF-κB nuclear translocation occur following cortical spreading depolarization (CSD) in wildtype (WT) mice but it is unknown to what extent this occurs in the migraine brain. We therefore investigated in familial hemiplegic migraine type 1 (FHM1) knock-in mice, which express an intrinsic hyperexcitability phenotype, the extent of neuroinflammation without and after CSD. CSD was evoked in one hemisphere by pinprick (single CSD) or topical KCl application (multiple CSDs). Neuroinflammatory (HMGB1, NF-κB) and neuronal activation (pERK) markers were investigated by immunohistochemistry in the brains of WT and FHM1 mutant mice without and after CSD. Effects of NMDA receptor antagonism on basal and CSD-induced neuroinflammatory changes were examined by, respectively, systemically administered MK801 and ifenprodil or topical MK801 application. In FHM1 mutant mice, CSD caused enhanced neuronal HMGB1 release and astrocytic NF-κB nuclear translocation in the cortex and subcortical areas that were equally high in both hemispheres. In WT mice such effects were only pronounced in the hemisphere in which CSD was induced. Neuroinflammatory responses were associated with pERK expression indicating neuronal activation. Upon CSD, contralateral cortical and striatal HMGB1 release was reduced by topical application of MK801 in the hemisphere contralateral to the one in which CSD was induced. This study reveals that neuroinflammatory activation after CSD is widespread and extends to the contralateral hemisphere, particularly in brains of FHM1 mutant mice. Effective blockade of CSD-induced neuroinflammatory responses in the contralateral hemisphere in FHM1 mice by local NMDA receptor antagonism suggests that neuronal hyperexcitability-related neuroinflammation is relevant in migraine pathophysiology, but possibly also other neurological disorders in which spreading depolarization is involved.

Effect of Sources, Split and Foliar Application of KCl and KClO3 on Availability and Uptake of Phosphorus in Aerobic Rice

Aim: To investigate the effect of KCl and KClO3 as sources of potassium in aerobic rice with four types of split doses and two levels of foliar applications of potassium.
 Study Design: The experiment was laid out in Randomized Block Design with three replications.
 Place and Duration of Study: Pandit Jawaharlal Nehru College of Agriculture and Research Institute, Karaikal, Puducherry.
 Methodology : The rice variety PMK 4 was tested with two sources of potassium viz., Potassium chloride (KCl) and Potassium chlorate (KClO3), four types of split application viz., K control (S1), basal with no split (S2), two splits (S3) and three splits (S4) along with foliar application treatments viz., no foliar (F1) and foliar spray (F2).
 Results: The results of a field experiment revealed that the two splits of potassium increased the available P at the active tillering stage and harvest stage. Whereas, three splits increased the available P at panicle imitation and flowering stage. The KCl recorded higher available P at panicle initiation and harvest stages. The high phosphorus uptake was recorded in panicle initiation and flowering stages by three splits application of potassium. In grain also, especially the three splits through KClO3 recorded higher P uptake.
 Conclusion: The split applications tested in this investigation influenced the available phosphorus status in soil and phosphorus uptake. Increase in splits of potassium increased the P uptake. This result is in agreement with the results of Mitra et al. [1] who observed a significant increase in the uptake of N, P, K and S by increased level of K in Kharif rice.

Effect of Sources, Split and Foliar Application of KCl and KClO3 on Availability and Uptake of Nitrogen in Aerobic Rice

Aim: To investigate the effect of KCl and KClO3 as sources of potassium in aerobic rice with four types of split doses and two levels of foliar applications of potassium.
 Study Design: The experiment was laid out in Randomized Block Design with three replications.
 Place and Duration of Study: Pandit Jawaharlal Nehru College of Agriculture and Research Institute, Karaikal, Puducherry.
 Methodology: The rice variety PMK 4 was tested with two sources of potassium viz., Potassium chloride (KCl) and Potassium chlorate (KClO3), four types of split application viz., K control (S1), basal with no split (S2), two splits (S3) and three splits (S4) along with foliar application treatments viz., no foliar (F1) and foliar spray (F2).
 Results: The results of field experiment revealed that the N availability in soil was more at all stages of crop growth by two and three split doses of potassium. The KClO3 increased the available N status at active and panicle initiation stages. Whereas in flowering stage, the KCl recorded the higher available N status in soil. The nitrogen uptake at active tillering stage and flowering stage was evidently improved with three split doses of potassium. Whereas in panicle initiation stage, the two split doses registered higher N uptake. The nitrogen uptake by both grain and straw was conspicuously higher in three and two split doses of potassium.
 Conclusion: The split applications tested in this investigation influenced the available N status in soil. Almost in all the stages, three split applications retained more available N in soil. This implies the positive interaction of potassium with nitrogen.

Potassium supply promotes the mitigation of NaCl-induced effects on leaf photochemistry, metabolism and morphology of Setaria viridis

Soil salinity has the potential to severely affect crop performance. To maintain cell functioning and improve salt tolerance, the maintenance of K+ homeostasis is crucial in several plant metabolism processes. Besides, potassium fertilization can efficiently alleviate the perilous effects of salinity. We characterized impacts in Setaria viridis exposed to NaCl and KCl to underlying photochemistry mechanisms, K+ and Na+ shoot contents, enzymatic activity, electrolytic leakage, and morphological responses focusing on non-stomatal limitation of photosynthesis. Plants were exposed to sodium chloride (NaCl; 0, 150 and 250 mM) and potassium chloride (KCl; 0, 5, 9 mM). The exposure to NaCl affected S. viridis leaves morphological and physiologically. Plants submitted to 150 mM showed reductions in performance indexes (PIabs and PItotal; JIP-test), and the presence of positive K- and L-bands. Plants exposed to 250 mM exhibited blockage in electron flow further than QA within 48h and permanent photoinhibition at 96 h. The presence of 9 and 5 mM of KCl counteracted the effects of NaCl on plants submitted to 150 mM, concomitant with increases in K+ accumulation and cell turgidity conservation, causing positive effects in plant growth and metabolism. Neither KCl concentrations were effective in reducing NaCl-induced effects on plants exposed to 250 mM of NaCl. Our results support the conclusion that greater availability of K+ alleviates the harmful effects of salinity in S. viridis under moderate stress and that application of KCl as means of lightning saline stress has a concentration and a salt level limit that must be experimentally determined.

Foliar application of potassium on antioxidant enzyme activities of tomato plants under drought stress

Water stress negatively affects productivity in crops, while the foliar application of potassium-containing compounds may be helpful in reducing the drought effects. This study evaluated the efficacy of foliar applied potassium chloride (control - distilled water spray -, 3 and 6 mM-1) on tomato plants under drought stress. Three irrigation levels were maintained at 100, 75 and 50% according to evapotranspiration designated as well watered, moderate and severe drought stressed. Increasing drought stress significantly reduced plant growth and yield. The foliar applied KCl produced maximum leaf area, stem diameter and length, plant yield under each drought stress conditions compared to control. The minimum of growth factors were obtained by control under severe stress. Highest yield per plant was also recorded for foliar applied KCl under moderate condition than other treatments. Foliar applied KCl alone decreased the SOD, CAT and PPO in well-watered condition but KCl application on tomato plants under drought stress induced the antioxidant enzyme activities more than control well-watered treatment.

A non-convulsant delta-opioid receptor agonist, KNT-127, reduces cortical spreading depression and nitroglycerin-induced allodynia.

The aim of this study was to determine if the non-convulsant delta-opioid receptor (DOR) agonist, KNT-127, could inhibit migraine-associated endpoints. The DOR has been identified as a therapeutic target for migraine. However, the development of delta agonists is limited as some ligands have seizurogenic properties, which may be related to their ability to induce receptor internalization. While both pro- and non-convulsant delta agonists can reduce migraine-associated allodynia, only the proconvulsant agonist, SNC80, has been shown to decrease cortical spreading depression (CSD). It is unclear if the ability of delta agonists to modulate cortical activity is related to the same signaling mechanisms that produce proconvulsant effects. The effects of the non-convulsant delta agonist, KNT-127, were examined. Repetitive CSD was induced in female C57BL6/J (n=6/group) mice by continuous application of KCl and the effect of KNT-127/vehicle (Veh) on both local field potentials and optical intrinsic signals was determined. To assess the effect of KNT-127 on established chronic migraine-associated pain, male and female C57BL6/J mice were treated with nitroglycerin (NTG; 10mg/kg, ip) every other day for 9days and tested with KNT-127 (5mg/kg, sc) or Veh on day 10 (n=6/group). DOR-enhanced green fluorescent protein mice (n=4/group) were used to confirm the internalization properties of KNT-127 in the trigeminal ganglia, trigeminal nucleus caudalis, and somatosensory cortex. KNT-127 inhibited CSD events (t(10) =3.570, p=0.0051). In addition, this delta agonist also reversed established cephalic allodynia in the NTG model of chronic migraine (F(1, 20) =12.80, p<0.01). Furthermore, KNT-127 caused limited internalization of DOR in key migraine processing regions. This study shows that the antimigraine effects of DOR agonists can be separated from their proconvulsant effects. This data provides valuable information for the continued development of delta agonists for the treatment of migraine.

Abstract 14278: Microglial Calcium Activity During Ischemic Stroke

Introduction: Ischemic stroke triggers waves of propagating action potentials followed by a loss of homeostatic ion gradients, known as cortical spreading depolarizations (SD). Our data indicate that microglia respond to SD by raising intracellular Ca 2+ , triggering a release of proinflammatory cytokines that may exacerbate post-stroke morbidity. Hypothesis: Inhibiting calcium release-activated calcium (CRAC) channels may block microglial Ca2+ influx and activation to potentially provide therapeutic benefit in ischemic stroke. Methods: We generated a mouse line expressing the Ca2+ indicator GCaMP5 in cortical microglia. Using two-photon microscopy, we imaged microglia in vivo following physical stroke via middle cerebral artery occlusion (MCAo) or chemical stroke via 1M KCl solution application. Controls were compared to mice treated with lipopolysaccharide (LPS) to mimic the inflammation of ischemic stroke. To study CRAC channels as a therapeutic target, we administered CM-EX-137, a CRAC channel blocker, and compared Ca2+ activity to controls. Results: We identified periodical Ca2+ waves in cortical microglia following MCAo (Fig. 1A), or localized KCl application (Fig. 1B-E). Further, when compared to controls, LPS-exposed mice expressed significantly greater microglial Ca2+ activity during KCl-triggered SD (Fig. 1C). Additionally, administration of CM-EX-137 effectively abolished the Ca2+ signals in the microglia and propagation of SD upon application of KCl (Fig. 1E). Conclusions: Blocking the Ca2+ influx into microglia after ischemic stroke may decrease the frequency of SD and reduce microglial activation, potentially leading to smaller stroke volumes and improved clinical outcomes. Figure 1: Microglial Ca 2+ after SD. (A) Ca 2+ transients in microglia after MCAo. (B) KCl-induced Ca 2+ activity in naïve microglia. (C) KCl-induced Ca 2+ activity after LPS. (D, E) KCl-induced Ca 2+ wave after (D) vehicle or (E) CM-EX-137 administration.

An underrepresented majority: A systematic review utilizing allodynic criteria to examine the present scarcity of discrete animal models for episodic migraine.

Despite increasing evidence differentiating episodic and chronic migraine, little work has determined how currently utilized animal models of migraine best represent each distinct disease state. In this review, we seek to characterize accepted preclinical models of migraine-like headache by their ability to recapitulate the clinical allodynic features of either episodic or chronic migraine. From a search of the Pu bMed database for "animal models of migraine", "headache models" and "preclinical migraine", we identified approximately 80 recent (within the past 20 years) publications that utilized one of 10 different models for migraine research. Models reviewed fit into one of the following categories: Dural KCl application, direct electrical stimulation, nitroglycerin administration, inflammatory soup injection, CGRP injection, medication overuse, monogenic animals, post-traumatic headache, specific channel activation, and hormone manipulation. Recapitulation of clinical features including cephalic and extracephalic hypersensitivity were evaluated for each and compared. Episodic migraineurs comprise over half of the migraine population, yet the vast majority of current animal models of migraine appear to best represent chronic migraine states. While some of these models can be modified to reflect episodic migraine, there remains a need for non-invasive, validated models of episodic migraine to enhance the clinical translation of migraine research.

Potassium Influencing Physiological Parameters, Photosynthesis and Sugarcane Yield in Subtropical India

Potassium plays an important role in the metabolism of plants, growth, development and yields. Worldwide, KCl is commonly used as source of K fertilizer in agricultural crops. The present experiment was taken up to assess the response of various sources of K on physiological attributes, yield and quality parameters of sugarcane. Treatments were no K application, potassium ammonium sulphate (H4KNO4S-9:0:30:20, NPKS ratio), slow release K fertilizer (0:0:45:0), sulphate of potash/potassium sulphate (K2SO4-0:0:50:17.5), muriate of potash (KCl-0:0:50:0) and muriate of potash (KCl) + elemental S @ 40 kg ha−1. Application of K2SO4 recorded 15.8% improvement in tiller population (during peak tillering stage) and 22.2% improvement in dry matter accumulation (at the harvest stage) over the KCl. About 12.33–24.16% increments in crop growth rate and the highest net photosynthetic rate (19.91 µmol m−2 s−1) were also recorded with application of K2SO4. Application of K fertilizers improved the availability of potassium in soil by 8.17% (254.2 kg ha−1). Potassium uptake in sugarcane crop ranged from 245 to 347 kg ha−1. The highest individual cane length (311 cm) was measured with application of K2SO4. Application of K2SO4 brings forth about 23.8% increments in millable canes, 14% in cane weight and 33.8% in cane yield over no K. Application of K also increased mean sucrose content in juice by 0.58 unit (17.0 pol per cent juice) over no use of K. Overall effect of K application on increasing sugarcane yield and sucrose content simultaneously brought forth improvement in commercial cane sugar (CCS) by 29.43% (10.50 t/ha) over no use of K. However, application of K2SO4 also improved CCS by 25.89% (11.67 t/ha) over the application of KCl.

Inhibition of NR2A reduces calcitonin gene-related peptide gene expression induced by cortical spreading depression in rat amygdala

Despite robust evidence on the role of calcitonin gene-related peptide (CGRP) in migraine via both central and peripheral actions, relatively less is known about how CGRP in the limbic system is involved in migraine progression. This study investigated whether CGRP production machinery exists in the two key limbic regions including hippocampus and amygdala using cortical spreading depression (CSD) as a model of migraine and whether such alteration by CSD is sensitive to N-methyl-d-aspartate (NMDA) receptor regulation in rats. A single or repetitive CSD was induced by topical application of KCl and monitored using electrophysiological methods. The NR2A-containing NMDA receptor antagonist, NVP-AAM077, or its vehicle, was perfused into the contralateral cerebroventricular ventricle of rat. Quantitative PCR was used to measure CGRP mRNA levels in the ipsilateral and contralateral hippocampus and amygdala after CSD events and compared to respective sham treatments. The results showed that neither a single CSD nor repetitive CSD affected CGRP mRNA levels in both the contralateral and ipsilateral hippocampus at 24 h post CSD induction. Differently, significant elevation of CGRP gene expression was observed in the ipsilateral amygdala at 24 h post multiple CSD, but not contralateral side, and not post-single CSD. Further results showed that the CSD-induced CGRP gene expression in the amygdala was markedly reduced by NVP-AAM077 and this reduction corresponded to a reduced cortical susceptibility to CSD in rats. We conclude that repetitive CSD events induce CGRP gene expression in amygdala, which is sensitive to NR2A regulation.

Nitrogen fertilization and potassium requirement for cereal crops under a continuous no-till system

Nitrogen (N) and potassium (K) are the most required nutrients for corn and wheat production. Increasing the N application rate usually boosts crop yields. However, many uncertainties remain for K management. Potassium deficiency results in yield losses, but K application rate based on the percentage of K+ in the cation exchange capacity (CEC) is doubtful, especially in soil with high CEC. A field trial was conducted to examine the effects of KCl application before sowing corn and wheat, by raising the percentage of K+ in CEC at pH 7.0 (CECpH7.0) to approximately 2.5%, 3.5%, and 4.5%, and adding N as a topdressing (75, 150, and 225 kg ha−1 to corn and 40, 80, and 120 kg ha−1 to wheat) on the nutrition and yield of corn and wheat under a continuous no-till system (30 years). Exchangeable K+ content increased in the topsoil (0–20 cm depth) up to 7.2 mmolc dm−3 after K application at the highest rate, which, however, did not result in significant increases in nutrient uptake and yields for both corn and wheat. The N application rate positively affected the uptake and removal of all macronutrients by corn and wheat. Applying N as a topdressing increased yields of corn and wheat by up to 83% and 22%, respectively. Our results suggest that in the soil with a high CECpH7.0 (162.1 mmolc dm−3), the recommendation for K application made by considering the percentage of K+ in the CECpH7.0 may result in excessive application of K fertilizer to crops with high K-recycling potential grown under a continuous no-till system.

Spreading Depolarization Facilitates the Transition of Neuronal Burst Firing from Interictal to Ictal State

The transition of neuronal burst firing from the interictal to ictal state contributes to seizure initiation in human temporal lobe epilepsy. The low-Mg2+ model of seizure is characterized by initial spontaneous interictal bursting events, which later developed into ictaform discharges. Both experimental and clinical studies point to a complex link between spreading depolarization (SD) and epileptiform field potentials (EFP), including SD-induced epileptic seizures. To investigate the mechanism of SD and EFP interactions, the effect of SD on the transition of interictal to ictal state in low-Mg2+ model of seizure was studied in the rat hippocampus in vitro. After the appearance of interictal activities, SD was elicited by local application of KCl. SD significantly increased the amplitude and duration of action potentials and after-hyperpolarization, and hyperpolarized the membrane potential. Furthermore, SD significantly increased the duration of interictal activities and the threshold potentials of interictal activities. In addition, SD significantly accelerated the transition from interictal to ictal state compared to the control tissues. Ictal activities after induction of SD exhibited a significantly longer duration. This study revealed that SD accelerates interictal-to-ictal transitions and facilitates development of ictaform discharges, possibly via the enhancement of neural synchronization, and points to the potential role of SD in seizure initiation.