Dietary vitamin D is a novel modulator of tumor engraftment through regulation of GC protein abundance

The vitamin D binding protein, the GC protein, is a multifunctional protein that binds circulating vitamin D and also increases macrophage killing of tumor cells. Injecting exogenous GC protein concurrent with experimental tumor implant decreases tumor engraftment rate. Until now serum abundance of this protein was thought to be controlled by estrogen, glucocorticoids and inflammatory cytokines, but, not by vitamin D itself(1, 2). Nonetheless, increasing dietary vitamin D is thought to increase serum vitamin D, which is 98% bound by the GC protein. Based on the protection that excess GC protein offers we sought to determine if decreased GC protein abundance might decrease tumor immunity. Relatedly, we theorized, by contrast to the current model, that dietary vitamin D might affect serum abundance of GC protein. If exogenous vitamin D alters available GC levels, then this effect might indicate a novel pathway by which vitamin D enhances immunity. To examine these possibilities, we examined the effect of GC protein absence on tumor persistence or engraftment on two different and common tumor types (prostate cancer and breast cancer). We further examined the relationship between dietary vitamin D and serum GC abundance. We found that absence of GC protein allowed significantly more engraftment of breast tumor cells in female mice and of prostate tumor cells in male mice. Further, we found a U-shaped response of serum GC protein to dietary vitamin D dosage as well as to serum vitamin D, indicating the potential benefit of high exogenous doses to enhance immunity and reduce tumor burden.

A pilot randomized clinical trial of intranasal oxytocin to promote weight loss in individuals with hypothalamic obesity

Context

Hypothalamic obesity is a rare, treatment-resistant form of obesity. In preliminary studies, the hypothalamic hormone oxytocin (OXT) has shown promise as a potential weight loss therapy.

Objective

To determine whether 8 weeks of intranasal OXT (vs. 8 weeks of placebo) promotes weight loss in children, adolescents, and young adults with hypothalamic obesity.

Design

Randomized, double-blind, placebo-controlled, cross-over pilot trial (NCT02849743).

Setting

Outpatient academic medical center.

Participants

Aged 10y to 35y, hypothalamic obesity from hypothalamic/pituitary tumors.

Intervention

Intranasal OXT (Syntocinon, 40 USP units/mL, 4 IU/spray) vs. excipient-matched placebo, 16-24 IU three times daily at mealtimes.

Main outcome measure(s)

Weight loss attributable to OXT vs. placebo, safety (adverse events).

Results

Of 13 individuals randomized (54% female, 31% pre-pubertal, median age 15.3y, IQR 13.3-20.6), 10 completed the entire study. We observed a non-significant within-subject weight change of -0.6 kg (95% CI: -2.7, 1.5) attributable to OXT vs. placebo. A subset (2/18 screened, 5/13 randomized) had prolonged QTc interval on electrocardiography (ECG) prior to screening and/or in both treatment conditions. Overall, OXT was well-tolerated, and adverse events (epistaxis and nasal irritation, headache, nausea/vomiting, and changes in heart rate, blood pressure, and QTc interval) were similar between OXT and placebo. In exploratory analyses, benefits of OXT for anxiety and impulsivity were observed.

Conclusions

In this pilot study in hypothalamic obesity, we did not detect a significant impact of intranasal OXT on body weight. OXT was well-tolerated, so future larger studies could examine different dosing, combination therapies, as well as potential psychosocial benefits.

Improved genetic risk scoring algorithm for type 1 diabetes prediction

BACKGROUND

Precise risk prediction of type 1 diabetes (T1D) facilitates early intervention and identification of risk factors prior to irreversible beta-islet cell destruction, and can significantly improve T1D prevention and clinical care. Sharp et al. developed a genetic risk scoring (GRS) system for T1D (T1D-GRS2) capable of predicting T1D risk in children of European ancestry. The T1D-GRS2 was developed on the basis of causal genetic variants, thus may be applicable to minor populations, while a trans-ethnic GRS for T1D may avoid the exacerbation of health disparities due to the lack of genomic information in minorities.

METHODS

Here, we describe a T1D-GRS2 calculator validated in two independent cohorts, including African American children and European American children. Participants were recruited by the Center for Applied Genomics at the Children's Hospital of Philadelphia.

RESULTS

It demonstrates that GRS2 is applicable to the T1D risk prediction in the AA cohort, while population-specific thresholds are needed for different populations.

CONCLUSIONS

The study highlights the potential to further improve T1D-GRS2 performance with the inclusion of additional genetic markers.

Insights into non-autoimmune type 1 diabetes with 13 novel loci in low polygenic risk score patients

With polygenic risk score (PRS) for autoimmune type 1 diabetes (T1D), this study identified T1D cases with low T1D PRS and searched for susceptibility loci in these cases. Our hypothesis is that genetic effects (likely mediated by relatively rare genetic variants) of non-mainstream (or non-autoimmune) T1D might have been diluted in the previous studies on T1D cases in general. Two cohorts for the PRS modeling and testing respectively were included. The first cohort consisted of 3302 T1D cases and 6181 controls, and the independent second cohort consisted of 3297 T1D cases and 6169 controls. Cases with low T1D PRS were identified using PRSice-2 and compared to controls with low T1D PRS by genome-wide association (GWA) test. Thirteen novel genetic loci with high imputation quality (Quality Score r² > 0.91) were identified of SNPs/SNVs associated with low PRS T1D at genome-wide significance (P ≤ 5.0 × E-08), in addition to 4 established T1D loci, 3 reported loci by our previous study, as well as 9 potential novel loci represented by rare SNVs, but with relatively low imputation quality (Quality Score r² < 0.90). For the 13 novel loci, 9 regions have been reported of association with obesity related traits by previous GWA studies. Three loci encoding long intergenic non-protein coding RNAs (lncRNA), and 2 loci involved in N-linked glycosylation are also highlighted in this study.

Growth in Children with a Fontan Circulation

OBJECTIVE

To evaluate growth in a population of patients with Fontan circulation.

STUDY DESIGN

We performed a cross-sectional evaluation of patients followed in our multidisciplinary Fontan clinic from January 2011 through August 2015. We reviewed the historical data, anthropometry, clinical, and laboratory studies and performed bivariate and multivariate analysis of factors associated with height z score.

RESULTS

Patients (n = 210) were included in the study at median age 11.07 years (8.3, 14.73 years) (43% female); 138 (65%) had a dominant right systemic ventricle and 92 (44%) hypoplastic left heart syndrome. Median age at completion of Fontan circulation was 31 months (7.6, 135.8 months). Median height z score was -0.58 (-1.75, 0.26). Twenty-five (12%) had current or past history of protein-losing enteropathy (PLE). Median height z score for those with current or past history of PLE was -2.1 (-2.46, 1.24). Multivariate analysis revealed positive associations between height z score and body mass index z score, time since Fontan, mid-parental height, dominant systemic ventricle type, and serum alkaline phosphatase. Height correlated negatively with known genetic syndrome, PLE, use of stimulant or oral steroid medication.

CONCLUSIONS

Children with Fontan circulation have mild deficits in height, with greater deficits in those with PLE. Height z score improves with time postsurgery. Improving weight, leading to improved body mass index, may be a modifiable factor that improves growth in those who are underweight. Biochemical markers may be helpful screening tests for high-risk groups in whom to intensify interventions.

Genetic architecture of type 1 diabetes with low genetic risk score informed by 41 unreported loci

Type 1 diabetes (T1D) patients with low genetic risk scores (GRS) may be non-autoimmune or autoimmune mediated by other genetic loci. The T1D-GRS2 provides us an opportunity to look into the genetic architecture of these patients. A total of 18,949 European individuals were included in this study, including 6599 T1D cases and 12,323 controls. 957 (14.5%) T1D patients were identified with low GRS (GRS < 8.43). The genome-wide association study on these patients identified 41 unreported loci. Two loci with common variants and 39 loci with rare variants were identified in this study. This study identified common SNPs associated with both low GRS T1D and expression levels of the interferon-α-induced MNDA gene, indicating the role of viral infection in T1D. Interestingly, 16 of the 41 unreported loci have been linked to autism spectrum disorder (ASD) by previous studies, suggesting that genes residing at these loci may underlie both T1D and autism.

Association of DLL1 with type 1 diabetes in patients characterized by low polygenic risk score

Type 1 diabetes (T1D) is a heterogeneous disease. This study identified T1D cases with low polygenic risk score (PRS) to better represent T1D cases with less prominent autoimmune response (T1bD), and performed a gene-based association study to identify novel susceptibility loci in two independent cohorts, characterized by low PRS. The Notch ligand Delta-like 1 gene (DLL1) was identified with genome-wide significance in both cohorts, highlighting the roles of DLL1 genetic variants in T1D patients with low PRS, supported by functional evidence from a recent study by Rubey et al.

Differential Frequency of CYP2R1 Variants Across Populations Reveals Pathway Selection for Vitamin D Homeostasis

CONTEXT

Normal vitamin D homeostasis is necessary to ensure optimal mineral metabolism. Dietary insufficiency of vitamin D and the lack of sunlight each have well understood roles in vitamin D deficiency; however, the extent to which common genetic variations in vitamin D metabolizing enzymes contribute to alterations in vitamin D homeostasis remains uncertain.

OBJECTIVE

To examine the possibility that common coding variation in vitamin D metabolizing enzymes alters vitamin D homeostasis we determined the effect of 44 nonsynonymous polymorphisms in CYP2R1, the vitamin D 25-hydroxylase, on enzyme function.

RESULTS

Twenty-one of these polymorphisms decreased activity, while 2 variants increased activity. The frequency of CYP2R1 alleles with decreased 25-hydroxylase activity is 3 in every 1000 Caucasians and 7 in every 1000 African Americans. In populations where exposure to sunlight is high, alleles with decreased function occur at a frequency as high as 8%. The pattern of selected variation as compared to nonselected variation is consistent with it being the result of positive selection for nonfunctional alleles closer to the equator. To examine this possibility, we examined the variation pattern in another protein in the vitamin D pathway, the vitamin D binding protein (GC protein). The pattern of selected variation in the GC protein as compared to nonselected variation is also consistent with it being the result of positive selection for nonfunctional alleles closer to the equator.

CONCLUSIONS

CYP2R1 polymorphisms have important effects on vitamin D homeostasis, and the geographic variability of CYP2R1 alleles represents an adaptation to differential exposures to UVB irradiation from sunlight.

Obesity Decreases Hepatic 25-Hydroxylase Activity Causing Low Serum 25-Hydroxyvitamin D

Normal vitamin D homeostasis is critical for optimal health; nevertheless, vitamin D deficiency is a worldwide public health problem. Vitamin D insufficiency is most commonly due to inadequate cutaneous synthesis of cholecalciferol and/or insufficient intake of vitamin D, but can also arise as a consequence of pathological states such as obesity. Serum concentrations of 25(OH)D (calcidiol) are low in obesity, and fail to increase appropriately after vitamin D supplementation. Although sequestration of vitamin D in adipose tissues or dilution of ingested or cutaneously synthesized vitamin D in the large fat mass of obese patients has been proposed to explain these findings, here we investigate the alternative mechanism that reduced capacity to convert parent vitamin D to 25(OH)D due to decreased expression of CYP2R1, the principal hepatic vitamin D 25-hydroxylase. To test this hypothesis, we isolated livers from female mice of 6 to 24 weeks of age, weaned onto either a normal chow diet or a high-fat diet, and determined the abundance of Cyp2r1 mRNA using digital droplet-quantitative PCR. We observed a significant (p < 0.001) decrease in Cyp2r1 mRNA in the liver of high-fat diet-fed mice relative to lean-chow-fed female mice. Moreover, there was a significant (p < 0.01) relationship between levels of Cyp2r1 mRNA and serum 25(OH)D concentrations as well as between Cyp2R1 mRNA and the ratio of circulating 25(OH)D3 to cholecalciferol (p < 0.0001). Using linear regression we determined a curve with 25(OH)D3/cholecalciferol versus normalized Cyp2R1 mRNA abundance with an R2 value of 0.85. Finally, we performed ex vivo activity assays of isolated livers and found that obese mice generated significantly less 25(OH)D3 than lean mice (p < 0.05). Our findings indicate that expression of CYP2R1 is reduced in obesity and accounts in part for the decreased circulating 25(OH)D. © 2019 American Society for Bone and Mineral Research.

CLEC16A regulates splenocyte and NK cell function in part through MEK signaling

CLEC16A is implicated in multiple autoimmune diseases. We generated Clec16a inducible knockout (KO) mice to examine the functional link between CLEC16A auto-inflammation and autoimmunity. Clec16a KO mice exhibited weight loss and thymic and splenic atrophy. Mitochondrial potential was lowered in KO mice splenocytes resulting in aggregation of unhealthy mitochondria in B, T, and NK cells. In Clec16a KO mice we detected disrupted mitophagy in splenic B and T cells. NK cells from Clec16a KO mice exhibited increased cytotoxicity. Incomplete mitophagy was attenuated with PI3K and/or MEK inhibition in Clec16a KO mice. Our results demonstrate a functional link between CLEC16A and disrupted mitophagy in immune cells and show that incomplete mitophagy predisposes the KO mice to inflammation. Taken together, loss of function variants in CLEC16A that are associated with decreased CLEC16A expression levels may contribute to inflammation in autoimmunity through disrupted mitophagy. Drugs modulating mitophagy reverse the process and may be effective in treating and preventing autoimmunity in individuals with risk associated CLEC16A variants.

Decreased Serum 25-Hydroxyvitamin D in Aging Male Mice Is Associated With Reduced Hepatic Cyp2r1 Abundance

The prevalence of vitamin D deficiency, as determined by circulating levels of 25-hydroxycalciferol [25(OH)D], is greater in older individuals compared with the young. To examine the hypothesis that altered production or inactivation of 25(OH)D contributes to lower circulating levels of 25(OH)D, we measured the serum levels of parent vitamin D3 (cholecalciferol) and 25(OH)D. We also determined the relative abundance of transcripts encoding hepatic CYP2R1 and CYP27B1, the principal 25-hydroxylases, transcripts encoding enzymes that degrade 25(OH)D in the liver (Cyp3A11) and kidney (Cyp24A1) and transcripts encoding megalin and cubilin, proteins critical to vitamin D resorption in the kidney in mice at three different ages. We observed a significant decline in the relative abundance of Cyp2R1 in the liver with aging (one-way ANOVA, P = 0.0077). Concurrent with the decrease in mRNA, a significant decline in hepatic CYP2R1 protein (one-way ANOVA for trend, P = 0.007) and 25(OH)D (one-way ANOVA for trend, P = 0.002) and in the ratio of 25(OH)D3 to cholecalciferol (one-way ANOVA, P = 0.0003). By contrast, levels of the transcripts encoding Cyp3a11, Cyp24a1, and Cyp27b1 megalin and cubilin were unchanged with aging. A significant positive correlation was found between Cyp2r1 mRNA and 25(OH)D, and a stronger correlation was found between Cyp2r1 mRNA and the ratio of 25(OH)D3 to cholecalciferol. These results indicate that decreased expression of CYP2R1 contributes to the reduced serum levels of 25(OH)D in aging.

CYP3A4 mutation causes vitamin D-dependent rickets type 3

Genetic forms of vitamin D-dependent rickets (VDDRs) are due to mutations impairing activation of vitamin D or decreasing vitamin D receptor responsiveness. Here we describe two unrelated patients with early-onset rickets, reduced serum levels of the vitamin D metabolites 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D, and deficient responsiveness to parent and activated forms of vitamin D. Neither patient had a mutation in any genes known to cause VDDR; however, using whole exome sequencing analysis, we identified a recurrent de novo missense mutation, c.902T>C (p.I301T), in CYP3A4 in both subjects that alters the conformation of substrate recognition site 4 (SRS-4). In vitro, the mutant CYP3A4 oxidized 1,25-dihydroxyvitamin D with 10-fold greater activity than WT CYP3A4 and 2-fold greater activity than CYP24A1, the principal inactivator of vitamin D metabolites. As CYP3A4 mutations have not previously been linked to rickets, these findings provide insight into vitamin D metabolism and demonstrate that accelerated inactivation of vitamin D metabolites represents a mechanism for vitamin D deficiency.

Ablation of Oxytocin Neurons Causes a Deficit in Cold Stress Response

The paraventricular nucleus (PVN) is a critical locus of energy balance control. Three sets of neurons in the PVN are involved in regulating energy balance: oxytocin-expressing neurons (OXT-neurons), thyrotropin-releasing hormone–expressing neurons, and corticotrophin-releasing hormone–expressing neurons. To examine the role of OXT-neurons in energy balance, we ablated these neurons in mice by injecting diphtheria toxin into mice possessing both the oxytocin promoter driving cre expression and a cre-inducible diphtheria toxin receptor. Immunohistochemistry and real-time reverse transcriptase polymerase chain reaction confirmed that this injection caused a significant decrease in PVN OXT-neurons and OXT-mRNA abundance. OXT-neuron ablation did not alter food intake, weight, or energy expenditure at room temperature on either chow or a high-fat diet. To further characterize OXT-neuron–ablated mice, we examined their response to 1) intraperitoneal cholecystokinin (CCK) injection and 2) thermogenic stress. OXT-neuron–ablated mice had a blunted decrease in feeding response to CCK. When exposed to the extreme cold (4°C) for 3 hours, OXT-neuron–ablated mice had significant decreases in both rectal and brown adipose tissue temperature relative to controls, which was rescued by OXT treatment. Thermographic imaging revealed that OXT-neuron–ablated mice had increased body surface temperature. Thus, we report that OXT-neuron ablation shows no role for OXT-neurons in energy homeostasis at neutral temperature but reveals a heretofore unappreciated role for OXT-neurons and oxytocin specifically in regulating the thermogenic stress response.

Resting Energy Expenditure Is Decreased in Pseudohypoparathyroidism Type 1A

CONTEXT

Pseudohypoparathyroidism type 1A (PHP1A) is caused by loss-of-function mutations on the maternally inherited GNAS allele and is associated with early-onset obesity, neurocognitive defects, and resistance to multiple hormones. The role of energy intake vs central regulation of energy expenditure in the pathophysiology of obesity remains unclear.

OBJECTIVE

The aim of this study was to evaluate resting energy expenditure (REE) in participants with PHP1A.

DESIGN

We assessed REE, biochemical, endocrine, and auxological status of 12 participants with PHP1A who had normal or elevated body mass index; controls were a cohort of 156 obese participants.

SETTING

This study took place at Children's Hospital in Philadelphia and Sick Children's Hospital in Toronto.

MAIN OUTCOME MEASURES

REE as a percent of predicted REE was the outcome measure.

RESULTS

PHP1A participants had normal endocrine status while receiving appropriate hormone replacement therapy, but had significantly decreased REE as a percent of predicted REE (using the modified Schofield equation).

CONCLUSION

Our results are consistent with REE being the principal cause of obesity in PHP1A rather than it being caused by excessive energy intake or endocrine dysfunction.

Progress in understanding type 1 diabetes through its genetic overlap with other autoimmune diseases

Type 1 diabetes mellitus (T1DM) is the most common autoimmune disease in pediatrics with a prevalence of roughly 1 in 500 children in the USA. Genome-wide association studies have identified more than 50 variants associated with increased risk for type 1 diabetes. Comparison of these variants with those identified in other autoimmune diseases reveals three important findings: (1) there is a high degree of overlap in implicated variants in diseases with similar pathophysiology, (2) in diseases with differing pathophysiology the same variants are often implicated in opposite roles, (3) in diseases with differing pathophysiology that have many non-overlapping or oppositely implicated variants there are still several variants which are overlapping or shared. Thus, the genetic overlap between T1DM and other autoimmune diseases forms the basis for our understanding of druggable targets in type 1 diabetes.

Preterm birth without progesterone withdrawal in 15-hydroxyprostaglandin dehydrogenase hypomorphic mice

Parturition is a complex mammalian physiological process whose fundamental determinants have remained elusive. The increasing incidence of human preterm birth, a leading cause of infant mortality, highlights the importance of further understanding mechanisms regulating the timing of birth. Parturition is initiated in most nonprimate mammals, including mice, through a decrease in circulating progesterone caused by elevated prostaglandins. In humans, other higher primates, and guinea pigs, no consistent decrease in circulating progesterone occurs before the onset of labor. The divergence in endocrine control of labor initiation between most mammals compared with the great apes and guinea pigs gives rise to the question: how could a mechanism for the initiation of labor not requiring the withdrawal of progesterone evolve? Here, we genetically modulate prostaglandin signaling to determine the role of prostaglandin catabolism in the timing of birth. We find spontaneous preterm labor in the absence of progesterone withdrawal in 15-hydroxyprostaglandin dehydrogenase hypomorphic mice. The onset of labor in these hypomorphic mice is preceded by prematurely increased concentrations of prostaglandin E(2) and F(2alpha). Moreover, genetic crosses demonstrate a role for fetal genotype in birth timing. Together, these findings demonstrate a 15-hydroxyprostaglandin dehydrogenase-dependent shift in the physiology of murine parturition to one resembling the physiology of higher primates. Thus, endocrine control of labor has the capacity to plastically adapt to changes in genetically determined prostaglandin signals.

Modulation of recombinant small-conductance Ca(2+)-activated K(+) channels by the muscle relaxant chlorzoxazone and structurally related compounds

Using the patch clamp technique we investigated the effects of the centrally acting muscle relaxant chlorzoxazone and three structurally related compounds, 1-ethyl-2-benzimidazolinone (1-EBIO), zoxazolamine, and 1,3-dihydro-1-[2-hydroxy-5-(triflu oromethyl)phenyl]-5-(trifluoromethyl)-2H-benzimidazol-2-one (NS 1619) on recombinant rat brain SK2 channels (rSK2 channels) expressed in HEK293 mammalian cells. SK channels are small conductance K(+) channels normally activated by a rise in intracellular Ca(2+) concentration; they modulate the electrical excitability in neurons and neuroendocrine cells. When applied externally, chlorzoxazone, 1-EBIO, and zoxazolamine activated rSK2 channel currents in cells dialyzed with a nominally Ca(2+)-free intracellular solution. The activation was reversible, reproducible, and depended on the chemical structure and concentration. The order of potency was 1-EBIO > chlorzoxazone > zoxazolamine. Activation of rSK2 channels by chlorzoxazone, 1-EBIO, and zoxazolamine declined at higher drug concentrations. Zoxazolamine, when applied in combination with chlorzoxazone or 1-EBIO, partially inhibited the rSK2 channel current responses, suggesting a partial-agonist mode of action. 1-EBIO failed to activate rSK2 channel currents when applied to excised inside-out membrane patches exposed to a Ca(2+)-free intracellular solution. In contrast, 1-EBIO activated rSK2 currents in a concentration-dependent manner when coapplied to the patches with a solution containing 20 nM free Ca(2+). NS 1619 did not activate rSK2 channel currents; it inhibited rSK2 channel currents activated by the other three test compounds or by high intracellular Ca(2+). We conclude that chlorzoxazone and its derivatives act through a common mechanism to modulate rSK2 channels, and SK channel modulation in the brain may partly underlie the clinical effects of chlorzoxazone.

Block of rat brain recombinant SK channels by tricyclic antidepressants and related compounds

SK channels are small conductance, Ca(2+)-activated K(+) channels that underlie neuronal slow afterhyperpolarization and mediate spike frequency adaptation. Using the patch clamp technique, we tested the effects of eight clinically relevant psychoactive compounds structurally related to the tricyclic antidepressants, on SK2 subtype channels cloned from rat brain and functionally expressed in the human embryonic kidney cell line, HEK293. Amitriptyline, carbamazepine, chlorpromazine, cyproheptadine, imipramine, tacrine and trifluperazine blocked SK2 channel currents with micromolar affinity. The block was reversible and concentration-dependent. The potency differed according to chemical structure. In contrast, the cognitive enhancer linopirdine was ineffective at blocking these channels. Our results point to a distinct pharmacological profile for SK channels.

Patch-clamp analysis of anesthetic interactions with recombinant SK2 subtype neuronal calcium-activated potassium channels

Small conductance calcium-activated potassium channels (SK) mediate spike frequency adaptation and underlie the slow afterhyperpolarization in central neurons. We tested the actions of several anesthetics on the SK2 subtype of recombinant SK channels, cloned from rat brain and functionally expressed in a mammalian cell line. Butanol, ethanol, ketamine, lidocaine, and methohexital blocked recombinant SK2 channel currents, measured in the whole-cell patch clamp recording mode. The block was reversible, dose-dependent, and of variable efficacy. The inhaled anesthetics chloroform, desflurane, enflurane, halothane, isoflurane, and sevoflurane produced little or no block when applied at 1 minimum alveolar anesthetic concentration; varying degrees of modulation were observed at very large concentrations (10 minimum alveolar concentration). The extent of block by inhaled anesthetics did not appear to depend on concentration or membrane voltage.

IMPLICATIONS

We describe differential effects of anesthetics on cloned small conductance calcium-activated potassium channels from brain that may play a role in generating the effects or side effects of anesthetics.