Cholinergic stimulation of arachidonic acid and phosphatidic acid metabolism in C62B glioma cells

Glioma C62B cells were incubated for 18 h with [1-14C]arachidonic acid. Most (80%) of the added [1-14C] arachidonic acid was taken into the intracellular pool; less than 1% of the intracellular [1-14C]arachidonic acid remained unesterified; the rest was present in glycerophospholipids. Acetylcholine stimulation of the prelabeled cells resulted in the rapid accumulation of free [1-14C]arachidonic acid, presumably liberated by hydrolysis from phospholipids. Labeled unesterified [1-14C]arachidonic acid peaked by 90 s and returned to basal levels by 5 min. Paralleling the transient increase of unesterified [1-14C]arachidonic acid were increases in level of radioactivity in an unidentified lipoxygenase metabolite of arachidonic acid and of radioactive phosphatidic acid. The release of arachidonic acid induced by acetylcholine or carbachol was blocked by muscarinic but not nicotinic receptor antagonists; adrenergic or histaminergic receptor agonists were ineffective at stimulating arachidonic acid liberation. In contrast to the transient effects of stimulation with cholinergic agonists, stimulation with the divalent cation ionophore A23187 resulted in a linear increase in the accumulation of liberated arachidonic acid for at least 1 h. Furthermore, the pattern of metabolites synthesized from arachidonic acid in response to ionophore stimulation was more complex than that observed following cholinergic stimulation and included also several metabolites derived from cyclooxygenase activity. We conclude that muscarinic receptor agonists rapidly induce specific changes in arachidonic acid and phosphatidic acid metabolism in a glioma cell line and suggest that similar responses may occur in glial cells and play a physiologically significant role in neural metabolism

Associations between the LEP -2548G/A Promoter and Baseline Weight and between LEPR Gln223Arg and Lys656Asn Variants and Change in BMI z Scores in Arab Children and Adolescents Treated with Risperidone

Data on baseline (antipsychotic-naïve) age, weight, and height and change in these over three subsequent follow up time points up to 313.6 days (CI 303.5-323.7), were collected from 181 risperidone-treated children and adolescents (mean age 12.58 years, SD 4.99, range 2.17-17.7) attending a pediatric neurology clinic in Saudi Arabia. Owing to differences in genotypic distributions in subsamples, results are reported from the white Arabs (N=144). Age and gender-normed BMI-standardised z scores (BMI z) were calculated (lmsgrowth program). Linear regression was performed for baseline weight and BMI z, while change in BMI z was assessed using random effects ordered logistic regression. The following SNPs were analyzed: rs7799039 in the LEP promoter, rs1805094 (previously rs8179183), rs1137100 and rs1137101 in the LEPR, and rs1414334 in HTR2C. We found a nominally significant association between rs7799309 and baseline weight, adjusting for height, age, gender and diagnosis (A/G, P=0.035, β=-3.62, compared to G/G). rs1137101 (G/G, P=0.018, OR=4.13 compared to A/A) and rs1805094 C-allele carriers (P=0.019, OR=0.51) showed nominally significant associations with change in BMI z categories. Our data support and replicate previous relevant associations for these variants including with weight gain on risperidone, whilst being the first to report such associations in those of Arab ethnicity

Sistemas ganaderos familiares sostenibles: acuerdo de trabajo CALIMA - INIA.

Mediante un trabajo de tres años ejecutado por CALIMA con apoyo metodológico de INIA, la cooperativa implementó una propuesta técnica para cría vacuna que refleja las particularidades de su zona de influencia, en dos predios foco. Este artículo sintetiza los principales aspectos de la metodología, medidas implementadas y resultados alcanzados

Cholinergic stimulation of phosphatidylinositol hydrolysis by rat corneal epithelium in vitro

Phosphatidic acid (PA) is an obligate intermediate in the phosphatidylinositol (PI) cycle and may serve as a sensitive marker for this pathway of reactions. Previously, we have shown that acetylcholine (ACh) stimulates formation of labeled PA in whole rat corneas whose.phospholipids were prelabeled with [14C]arachidonate. To determine which layer of the cornea exhibits the ACh effect, intact epithelium was isolated from the rest of the corneal tissue (designated “stroma/ endothelium”) by incubating rat corneas with neutral protease and then stripping off the epithelium using forceps. The epithelium was ultra-structurally normal and avidly incorporated [14C]arachidonate into phospholipids; the stroma/endothelium had only trace incorporation. [14C]Arachidonyl-PA formation by the epithelium was significantly increased after a 37 second (+58%) and was maximal after a 5.0 minute (+188%) incubation in the presence of 1 mM ACh. The stimulation by ACh was blocked by atropine and scopolamine but not by d-tubocurarine. The epithelium also incorporated significant quantities of [3H]inositol into phosphatidylinositol (PI), phosphatidylinositol monophosphate (PIP), and phosphatidyl-inositol bisphosphate (PIP.). When [3H]inositol-labeled epithelia were incubated for 5 minutes with 1 mM ACh, [3H]inositol monophosphate (IP) was increased 200%, [3H]inositol bisphosphate (IP2) was increased 225%, and [3H]inositol trisphosphate (IP3) was increased 74%. These results suggest that muscarinic cholinergic receptors may be an important regulator of the PI cycle in corneal epithelium and thus may affect intracellular calcium mobilization and epithelial proliferation and regeneration