[Epidemioloical characteristics and economic burden analysis of palmoplantar pustulosis in urban areas of China].

Objective: To analyze the epidemiological characteristics and economic burden of palmoplantar pustulosis (PPP) in China. Methods: A population-based retrospective study was conducted using the data from China's Urban Basic Medical Insurance data from January 1, 2012, to December 31, 2016. International Classification of Diseases code and diagnoses in Chinese for PPP were used to identify cases and estimate the prevalence, incidence, and cost. Subgroup analyses were performed according to age and sex, and sensitivity analyses were conducted to evaluate the robustness of the results. Age-adjusted prevalence rates were calculated based on the 2010 national census data. Results: The crude prevalence and incidence rate of PPP in 2016 were 2.730/100 000 (95%CI: 2.218/100 000-3.242/100 000) and 1.556/100 000 (95%CI: 1.154/100 000-1.958/100 000), and the prevalence rate of females (2.910/100 000) was higher than that of males (2.490/100 000, χ2=97.48, P=0.001). The incidence rate of females (1.745/100 000) was also higher than that of males (1.418/100 000, χ2=85.02, P=0.001). The age peak of incidence and prevalence of patients with PPP was in the 30-39-year age group and a small peak existed in the 0-3-year age group among people under 20 years old. From 2012 to 2016, the average number of visits was (2.44±0.04) per patient, and the total per-capita cost per year was (982.40±39.19) yuan. Conclusion: In 2016, the prevalence and incidence rate of PPP in China were higher in females than in males, and the highest age peak was in the 30-39-year age group.

[The prognostic value of morphological and functional parameters of cardiac magnetic resonance in patients with systemic light chain amyloidosis].

Objective: To investigate the features of morphological and functional parameters of cardiac magnetic resonance (CMR) in patients with systemic light chain (AL) amyloidosis, and the prognostic values of these related parameters. Methods: The data of 97 patients (including 56 males and 41 females, aged 36 to 71 years) with AL amyloidosis from April 2016 to August 2019 in the General Hospital of Eastern Theater Command were retrospectively analyzed. All patients underwent CMR examination. Those patients were divided into survival (n=76) and death groups (n=21) according to the clinical outcomes, and the differences in clinical baseline and CMR parameters between the two groups were analyzed and compared. A smooth curve fitting was used to analyze the association between morphological and functional parameters and extracellular volume (ECV), and Cox regression models were conducted to explore the association between related parameters and mortality. Results: The left ventricular global function index (LVGFI), myocardial contraction fraction (MCF) and stroke volume index (SVI) decreased with increasing ECV [ß (95%CI) was -0.566 (-0.685--0.446), -1.201 (-1.424--0.977), -0.149 (-0.293--0.004), respectively;all P<0.05]. Left ventricular mass index (LVMI), and diastolic left ventricular global peak wall thickness (LVGPWT) increased with increasing ECV [ß(95%CI) was 1.440 (1.142-1.739), 0.190 (0.147-0.233), respectively;both P<0.001]. While left ventricular ejection fraction (LVEF) began to decrease only at higher amyloid burden (ß=-0.460, 95%CI:-0.639--0.280, P<0.001). The median follow-up time was 39 months (range 2-64 months), and 21 patients died during the follow-up period. The estimated survival rates according to Kaplan-Meier curves at 1, 3, and 5 years were 92.8%, 78.7%, and 77.1%, respectively. MCF<39% (HR=10.266, 95%CI: 4.093-25.747) and LVGFI<26% (HR=9.267, 95%CI: 3.705-23.178) were independent risk factors for death in patients with AL amyloidosis after adjusting for other CMR parameters (P<0.001). Conclusion: Multiple morphologic and functional parameters of CMR vary with the increase of ECV. MCF<39% and LVGFI<26% were independent risk factors for death.

Immune efficacy of DNA vaccines based on oprL and oprF genes of Pseudomonas aeruginosa in chickens.

Pseudomonas aeruginosa (P. aeruginosa) is a zoonotic pathogen that can infect a variety of animals, including poultry. However, as there is no commercial vaccine available it is imperative that new and effective vaccines are developed. In this study, 2 monovalent DNA vaccines (pOPRL and pOPRF), one divalent combination DNA vaccine (pOPRL+pOPRF) and one fusion DNA vaccine (pOPRLF) were constructed based on the oprL and oprF genes of P. aeruginosa. These vaccines were administered to chickens, an outer membrane protein vaccine (OMP vaccine) and inactivated vaccine used as positive controls. The serum antibody, interferon-γ (IFN-γ), interleukin-2 (IL-2) and interleukin-4 (IL-4) concentrations were determined and lymphocyte proliferation assays were performed. After challenging with virulent P. aeruginosa, protective efficacy was evaluated. Following vaccination, serum antibodies, stimulation index (SI) values, concentrations of IL-2 and IFN-γ in chickens vaccinated with the bivalent combination DNA vaccine and fusion DNA vaccine were found to be significantly higher than in those chickens vaccinated with the 2 monovalent DNA vaccines. Moreover, the immune indexes in the bivalent combination DNA vaccine group were higher than those in the fusion DNA vaccine group. However, the concentrations of IL-4 in the 4 DNA vaccine groups were of no significant difference. The protective efficacy rate provided by pOPRL, pOPRF, pOPRLF, pOPRL+pOPRF, inactivated vaccine and OMP vaccine were 53.3%, 40%, 66.7%, 80%, 93.3%, and 80%, respectively. The results indicate that DNA vaccines constructed with the oprL and oprF genes of P. aeruginosa, particularly the divalent combination DNA vaccine, represent better potential vaccines. This study has laid a foundation for the design and application of future DNA vaccines of P. aeruginosa.

New insights into mitogenomic phylogeny and copy number in eight indigenous sheep populations based on the ATP synthase and cytochrome c oxidase genes.

The origins and phylogeny of different sheep breeds has been widely studied using polymorphisms within the mitochondrial hypervariable region. However, little is known about the mitochondrial DNA (mtDNA) content and phylogeny based on mtDNA protein-coding genes. In this study, we assessed the phylogeny and copy number of the mtDNA in eight indigenous (population size, n=184) and three introduced (n=66) sheep breeds in China based on five mitochondrial coding genes (COX1, COX2, ATP8, ATP6 and COX3). The mean haplotype and nucleotide diversities were 0.944 and 0.00322, respectively. We identified a correlation between the lineages distribution and the genetic distance, whereby Valley-type Tibetan sheep had a closer genetic relationship with introduced breeds (Dorper, Poll Dorset and Suffolk) than with other indigenous breeds. Similarly, the Median-joining profile of haplotypes revealed the distribution of clusters according to genetic differences. Moreover, copy number analysis based on the five mitochondrial coding genes was affected by the genetic distance combining with genetic phylogeny; we also identified obvious non-synonymous mutations in ATP6 between the different levels of copy number expressions. These results imply that differences in mitogenomic compositions resulting from geographical separation lead to differences in mitochondrial function.

[Complete revascularization for multi-vessel coronary diseases through lower ministernotomy on beating heart off-pump surgery].

Objective: To discuss a novel method of complete revascularization for multi-vessel coronary diseases on beating heart off-pump surgery through lower ministernotomy. Methods: Clinical data of 79 patients underwent ministernotomy off-pump coronary artery bypass from January 2015 to May 2016 at Department of Cardiac Surgery, Heart Center, Beijing Friendship Hospital, Capital Medical University were analyzed retrospectively. There were 62 male and 17 female patients, with an average age of (65±9) years. All the patients were multi-vessel coronary diseases and planned to receive coronary artery bypass grafting. Left internal mammary artery, radial artery and great saphenous veins were harvested and prepared, respectively. The perioperative clinical data was observed and collected. Postoperative ventilator-assisted time, intensive care time, and 24-hour thoracic mediastinal drainage volume were recorded. Postoperative cardiac function was evaluated by echocardiography. The data were compared between pre- and post-operative using paired t test. Results: Cardiopulmonary bypass was used in 2 patients during operation because of unstable hemodynamic status, but the incision was not needed to extend for those 2 patients. The lower ministernotomy was converted to traditional full sternotomy in 2 patients due to limited space for proximal anastomosis. In total, 79 patients had an average of (2.8±0.6) grafts. One proximal anastomosis was performed in 75 patients and 2 anastomoses in 4 patients. Distal target vessels consisted of left descending arteries for 79 patients, posterior descending artery for 60 patients, obtuse marginal branch and intermediate branch for 56 patients and diagonal branches for 25 patients, respectively. Average postoperative ventilation time was (19.0±2.2) hours and ICU stay was (60±20) hours. One patient developed postoperative myocardial infarction and needed temporary intra-aortic balloon pump support. One patient was subjected to incision infection. None of patient died in this study. There were no significant differences in left ventricular end-diastolic diameter and left ventricular end-systolic diameter between pre- and post-operative. The post-operative ejection fraction was significantly higher than that pre-operative (66.5%±1.6% vs. 61.2%±2.3%, t=4.30, P=0.00). Conclusion: With lower ministernotomy, the various sites of distal target vessels could be reached and complete revascularization could be achieved for selected patients with triple vessel diseases, although the procedure is technical demanding.

Complete chloroplast genome sequence of cultivated Morus L. species.

The complete chloroplast genome (cpDNA) sequences of two cultivated species of Morus L. (Morus atropurpurea and Morus multicaulis) are reported and reconstructed in this study, and were compared with that of wild Morus mongolica. In M. atropurpurea, the circular genome is 159,113 bp in size and comprises two identical inverted repeat (IR) regions of 25,707 bp each, separated by a large single-copy (LSC) region of 87,824 bp and a small single-copy (SSC) region of 19,875 bp. The cpDNA sequence of M. multicaulis is longer than that of M. atropurpurea (159,154 bp), and consists of two IRs (25,678 bp), a LSC region (87,763 bp), and a SSC region (20,035 bp). Each cpDNA contains 112 unique genes including 78 protein-coding genes, 30 transfer RNA genes, and 4 ribosomal RNA genes, with a GC content of 36.2%. There were 83 simple sequence repeats (SSRs) with mononucleotides being the most common (60) and di-, tri-, tetra-, and hexanucleotides appearing less frequently in M. atropurpurea. M. multicaulis contains 81 SSRs containing 63 mononucleotide repeats. The genes and SSRs identified in this study may enhance understanding of cpDNA evolution at both intra- and interspecific levels. MEGA 6.0 was used to construct a phylogenetic tree of 27 species, which revealed that M. atropurpurea and M. multicaulis are more related to their congeners than to others. The cpDNA of M. atropurpurea and M. multicaulis and its structural analysis are important for the chloroplast genome project, development of molecular markers for Morus species, and breeding of varieties.

Immunotherapy for Lewis lung carcinoma utilizing dendritic cells infected with CK19 gene recombinant adenoviral vectors.

Dendritic cells (DCs) as 'professional' antigen-presenting cells (APCs) initiate and regulate immune responses to various antigens. DC-based vaccines have become a promising modality in cancer immunotherapy. Cytokeratin 19 (CK19) protein is expressed at high levels in lung cancer and many other tumor cells, suggesting CK19 as a potential tumor­specific target for cancer immune therapy. We constructed a recombinant adenoviral vector containing the CK19 gene (rAd-CK19). DCs transfected with rAd-CK19 were used to vaccinate C57BL/6 mice bearing xenografts derived from Lewis lung carcinoma (LLC) cells. The transfected DCs gave rise to potent CK19-specific cytotoxic T lymphocytes (CTLs) capable of lysing LLC cells. Mice immunized with the rAd­CK19-DCs exhibited significantly attenuated tumor growth (including tumor volume and weight) when compared to the tumor growth of mice immunized with rAd-c DCs or DCs during the 24-day observation period (P<0.05). The results revealed that the mice vaccinated with the rAd-CK19-DCs exhibited a potent protective and therapeutic antitumor immunity to LLC cells in the subcutaneous model along with an inhibitive effect on tumor growth compared to the mice vaccinated with the rAd-c DCs or DCs alone. The present study proposes a meaningful mode of action utilizing rAd-CK19 DCs in lung cancer immunotherapy.

Genetic features of a translation initiation system composed of IRES element, nucleotide context surrounding the initiation codon, and translation initiation region of classical swine fever virus RNA.

Nucleotide and codon usage are typically examined to investigate viral evolution. In this study, we analyzed the genetic information of 46 strains of classical swine fever virus (CSFV) RNA, nucleotide usage in the internal ribosome entry site (IRES), the nucleotide context surrounding the initiation codon, and synonymous codon usage in the translation initiation region. Phylogenetic analysis of the IRES element indicated that the genetic diversity of this element is generally similar to the phylogenetic clusters of CSFV genotypes. Nucleotides surrounding the initiation codon of CSFV RNA were generally more stable (ACAUGGCACAUGGAGUUG) compared to the internal AUG in the CSFV coding sequence. The second codon position after the initiation codon was generally selected to be GAG, which has lower tRNA abundance in pigs than its synonymous member (GAA). Regarding the synonymous codon usage bias in the CSFV translation initiation region, some codons showing low tRNA abundance in pigs are more frequently located in the translation initiation region than in the open reading frame of CSFV. Although CSFV, similarly to other RNA viruses, has a high mutation rate in nature, the regulatory features of nucleotide and synonymous codon usage of the IRES element, the nucleotide context surrounding the initiation codon and the translation initiation region in CSFV RNA have been 'branded' in the system of translation initiation to accommodate gene expression mediated by the cap-independent translation mechanism.

Characteristics of synonymous codon usage bias in the beginning region of West Nile virus.

Adaptation in the overall codon usage pattern of West Nile virus (WNV) to that of two hosts was estimated based on the synonymous codon usage value (RSCU). Synonymous codon usage biases for the beginning coding sequence of this virus were also analyzed by calculating the usage fluctuation for each synonymous codon along the target region (the first 270 codon sites of the whole coding sequence of WNV). Adaptation of WNV to Anopheles gambiae regarding the overall codon usage revealed a mixture of synonymous codon usage patterns between this virus and its vector. Regarding the adaptation of WNV to its dead-end host and codon usage, although a mixture of overall codon usage patterns exists, the number of codons with reversed tendency codon usage is lower than that between the virus and its vector. In addition, some codons with low RSCU values for this virus are highly selected in the beginning translation region of WNV, while codons with low RSCU values in this region tend to pair with tRNAs present in low abundance in the host, suggesting that highly selected codons in a specific region in the beginning region of WNV are, to some degree, influenced by the corresponding low tRNA abundance of hosts to regulate the translation speed of the WNV polyprotein.

The characteristics of synonymous codon usage in the initial and terminal translation regions of encephalomyocarditis virus.

The synonymous codon usage patterns in the initial and terminal translation regions (ITR, TTR) of the whole coding sequence of encephalomyocarditis virus (EMCV) were analyzed in relation to those in its natural hosts using the sequences accessible in databases. In general, some low-usage host codons were found over-represented in the ITR and TTR of the virus, while some high-usage host codons were found under-represented in the two viral regions. These relationships are thought to participate in the regulation of the speed of translation of viral proteins and in the suppression of ribosomal traffic jams, both aiming at the increase of virus yields.

Mapping codon usage in sequence regions flanking cleavage positions in the hepatitis A virus polyprotein.

To analyze the synonymous codon usage patterns of sequence regions flanking cleavage sites in the hepatitis A virus (HAV) polyprotein, the codon usage bias at codon positions and the synonymous codon usage in the target contexts of 30 virus strains were estimated by two simple methods that were based on the values for relative synonymous codon usage. In addition, the pattern of synonymous codon usage was compared between the genomic sequences in HAV and those of its human host. Our results indicated that HAV adopts a combination of coincidence and antagonism with the synonymous codon usage in humans. This characteristic may help HAV to efficiently use the translational machinery in its human host. We also observed that codon usage exhibited a strong bias in some specific positions in these contexts, and that the underrepresented synonymous codons, CUA for Leu, ACG for Thr, GUA for Val, and UCG for Ser, are preferentially used in these positions. These underrepresented synonymous codons likely play roles in regulating the rate of protein translation and influencing the secondary structure of the sequence regions flanking the cleavage sites.

Polymorphism in PGLYRP-1 gene by PCR-RFLP and its association with somatic cell score in Chinese Holstein.

Bovine peptidoglycan recognition protein 1 (PGLYRP-1), an important pattern recognition molecule (PRM) of the innate immune system, is an effector molecule in killing different microorganisms directly. To investigate whether the PGLYRP-1 gene was associated with mastitis and milk production traits in dairy cattle, the polymorphism of this gene was analyzed by PCR-RFLP in a population of 524 Chinese Holstein. A total of ten single nucleotide polymorphism (SNP) loci were identified. The association analysis of single SNP locus showed that T-35A, T-12G and G+102C were significantly associated (P<0.05) with somatic cell score (SCS), while G+102C and G+649C were significantly associated (P<0.05) with 305-day milk yield. Association analysis between combined haplotypes and SCS, milk production traits indicated that H3H3 was associated with the lower SCS (P<0.01), and H2H2 was associated with the lower 305-day milk yield (P<0.01). These findings demonstrated that polymorphisms in PGLYRP-1 gene associated with mastitis resistance and 305-day milk yield, and the H3H3 would provide a useful genetic marker of combined haplotypes for mastitis resistance selection and breeding in Chinese Holstein.

Polymorphism in PGLYRP-2 gene by PCR-RFLP and its association with somatic cell score and percentage of fat in Chinese Holstein.

Peptidoglycan recognition protein 2 (PGLYRP-2), which belongs to the PGRP family, is the only member that has no direct bactericidal activity but has N-acetylmuramoyl-l-alanine amidase activity. This feature of PGLYRP-2 indicates that it may play an important role in eliminating the pathogen associated molecular pattern (PAMP), such as peptidoglycan (PGN), which can reduce leukocytes in blood and lower somatic cell count (SCC) in milk. To investigate whether the PGLYRP-2 gene is associated with mastitis and milk production traits in dairy cattle, the polymorphism of this gene was analyzed by PCR-RFLP in a population of 546 Chinese Holstein cows. A total of five single nucleotide polymorphism (SNP) loci were identified. The association analysis of a single SNP locus showed that the C+4867T locus was significantly associated (P < 0.05) with somatic cell score (SCS). Surprisingly, all loci were significantly associated (P < 0.01 or P < 0.05) with percentage of fat. Association analysis between combined genotypes and SCS and milk production traits indicated that H2H2 was associated with higher percentage of fat (P < 0.05). These findings demonstrated that SNPs in PGLYRP-2 gene were related to mastitis resistance and percentage of fat, and that H2H2 would be a useful genetic marker of combined genotypes for breeding of Chinese Holstein.

Cholinergic modulation of non-N-methyl-D-aspartic acid glutamatergic transmission in the chick ventral lateral geniculate nucleus.

Neurotransmission between glutamatergic terminals of retinal ganglion cells and principal neurons of the ventral lateral geniculate nucleus (LGNv) was examined with patch clamp recordings in chick brain slices during electrical stimulation of the optic tract. Since muscarinic and nicotinic receptors are present in high densities in LGNv, the present study examined possible roles of both receptors in modulating retinogeniculate transmission. During whole-cell recordings from LGNv neurons, acetylcholine (ACh, 100 microM) caused an initial increase in amplitudes of optic tract-evoked non-N-methyl-D-aspartic acid (NMDA) glutamatergic postsynaptic currents (PSCs). This increase was unchanged when 1 microM atropine was present, indicating that this initial enhancement of PSCs was due entirely to activation of nicotinic receptors. However, during washout of ACh the amplitudes of evoked PSCs became significantly decreased by 40.4+/-5.0% for several minutes before recovering to their original amplitudes, an effect blocked by 1 microM atropine. Exogenously applied muscarine (10 microM) markedly depressed optic tract-evoked PSCs, and this decrease in amplitude was blocked by atropine. In a second set of experiments, we examined effects of releasing endogenous ACh prior to optic tract stimulation. This was accomplished by stimulation of the lateral portion of LGNv via a separate conditioning electrode. Following a brief train of low intensity conditioning stimuli, non-NMDA glutamatergic PSCs evoked by optic tract stimulation were potentiated. However, at higher conditioning stimulus intensities the PSCs were markedly decreased compared with control, and this decrease was partially blocked by atropine (1 microM). Neither ACh nor muscarine altered amplitudes of PSCs elicited by exogenously applied glutamate. Muscarine significantly reduced the frequency but not the amplitudes of miniature PSCs, consistent with a presynaptic location for muscarinic receptors mediating these effects. Thus while activation of nicotinic receptors potentiates retinogeniculate transmission, activation of muscarinic receptors mediates depression of transmission, demonstrating a complex cholinergic modulation of sensory information in LGNv.

Nicotinic receptor-mediated biphasic effect on neuronal excitability in chick lateral spiriform neurons.

Local neuronal circuits integrate synaptic information with different excitatory or inhibitory time windows. Here we report that activation of nicotinic acetylcholine receptors (nAChRs) leads to biphasic effects on excitability in chick lateral spiriform (SPL) neurons during whole cell recordings in brain slices. Carbachol (100 microM in the presence of 1 microM atropine) produced an initial short-term increase in the firing rates of SPL neurons (125+/-14% of control) that was mediated by postsynaptic nAChRs. However, after 3 min exposure to nicotinic agonists, the firing rate measured during an 800 ms depolarizing pulse declined to 19+/-7% (100 microM carbachol) or 26+/-8% (10 microM nicotine) of the control rate and remained decreased for 10-20 min after washout of the agonists. Similarly, after 60 s of electrically-stimulated release of endogenous acetylcholine (ACh) from cholinergic afferent fibers, there was a marked reduction (45+/-5% of control) in firing rates in SPL neurons. All of these effects were blocked by the nAChR antagonist dihydro-beta-erythroidine (30 microM). The inhibitory effect was not observed in Ca(2+)-free buffer. The nAChR-mediated inhibition depended on active G-proteins in SPL neurons and was prevented by the GABA(B) receptor antagonist phaclofen (200 microM), while the GABA(B) receptor agonist baclofen (10 microM) decreased firing rate in SPL neurons to 13+/-1% of control. The inhibitory response thus appears to be due to a nAChR-mediated enhancement of presynaptic GABA release, which then activates postsynaptic GABA(B) receptors. In conclusion, activation of nAChRs in the SPL initiates a limited time window for an excitatory period, after which a prolonged inhibitory effect turns off this window. The prolonged inhibitory effect may serve to protect SPL neurons from excessive excitation.

Efficacy and safety of telmisartan vs. losartan in control of mild-to-moderate hypertension: a multicentre, randomised, double-blind study.

This multicentre, randomised, double-blind, double-dummy, parallel-group study compared the efficacy and safety of telmisartan with those of losartan after 8 weeks' treatment. In total, 330 patients with mild-to-moderate hypertension (systolic blood pressure [SBP] <180 mmHg; diastolic blood pressure [DBP] 95-109 mmHg) were randomly assigned to receive once-daily treatment with telmisartan 40 mg (n = 164) or losartan 50 mg (n = 166). After 4 weeks' treatment, if a patient's DBP was > or = 90 mmHg, the dose was increased to telmisartan 80 mg or losartan 100 mg, respectively. The results show that mean trough seated blood pressure was reduced significantly more in the telmisartan group than that in the losartan group (SBP 12.5 mmHg vs. 9.4 mmHg, p = 0.037; DBP 10.9 mmHg vs. 9.3 mmHg, p = 0.030). The overall DBP response rate (reduction from baseline in mean seated DBP > or = 10 mmHg and/or a mean seated DBP <90 mmHg) at the end of the study in the telmisartan group was higher than that in losartan group (70.1% vs. 58.7%, p = 0.020). At both the low and high doses, the DBP response rates for telmisartan were significantly higher than those for losartan (telmisartan 40 mg vs. losartan 50 mg: 46.3% vs. 32.5%, p = 0.010; telmisartan 80 mg vs. losartan 100 mg: 79.3% vs. 65.3%, p = 0.008). Adverse events with the two treatments were comparable (telmisartan vs. losartan 23.2% vs. 22.9%, p = 0.952). Most events were mild in intensity and abated within 72 h. Thus, telmisartan 40 mg or 80 mg administered once daily can reduce SBP and DBP effectively and safely.

A novel choline-sensitive nicotinic receptor subtype that mediates enhanced GABA release in the chick ventral lateral geniculate nucleus.

Nicotinic acetylcholine receptors modulate the release of GABA, glutamate, acetylcholine and dopamine in the brain. Here we describe a novel choline-sensitive nicotinic acetylcholine receptor that mediates enhanced GABA release in the chick ventral lateral geniculate nucleus. Whole-cell recordings in slices demonstrated that choline (0.03-10 mM), generally considered an alpha7-selective agonist, and carbachol (3-300 microM), a non-selective cholinergic agonist, both increased the frequency of spontaneous GABAergic events in ventral lateral geniculate nucleus neurons. Tetrodotoxin (0.5 microM) partially reduced responses to carbachol, but eliminated responses to choline. During long-term (5 min) exposure to choline the GABA enhancement was maintained until choline was washed out. Choline (300 microM) enhanced the frequency of spontaneous GABAergic events by 4.28-fold in control artificial cerebrospinal fluid. This choline-mediated enhancement was significantly reduced by the following nicotinic acetylcholine receptor antagonists: 1 microM dihydro-beta-erythroidine (1.49-fold increase, P<0.001), 1 microM methyllycaconitine (1.53-fold, P<0.001) and 0.2 microM alpha-conotoxin ImI (1.84-fold, P<0.001). In contrast, no significant change was seen in the presence of 0.1 microM dihydro-beta-erythroidine, 0.1 microM methyllycaconitine, 0.1 microM alpha-bungarotoxin, 0.1 microM alpha-conotoxin MII, 0.1 microM kappa-bungarotoxin, or 1 microM alpha-conotoxin AuIB. These results indicate that choline, at concentrations as low as 100 microM, activates a nicotinic acetylcholine receptor that is distinct from the classical alpha7 nicotinic acetylcholine receptors previously known to be activated by choline.