家兔房水中双氯芬酸胆碱的平均药-时曲线的测定

目的探索双氯芬酸胆碱滴眼液点眼后的房水药代动力学行为。方法取24只家兔，随机平均分成0．25、0．5、0．75、1、2、4、8、12h8个时间组，用微量进样器滴入双氯芬酸钠胆碱(DAC)滴眼液100μL，分别于8个时间点取不少于200μL的房水样品。采用甲醇-乙腈-pH6．4磷酸盐(25：25：50)为流动相，Zor bax SBC18色谱柱为固定相的高效液相色谱法测定各时间点房水中双氯芬酸胆碱的质量浓度。结果家兔单剂量应用双氯芬酸胆碱滴眼液100μL后，房水中15min后即可检测到药物，且无其他杂质峰干扰，用不同时间点房水中的双氯芬酸胆碱药物质量浓度对时间作图，得其药-时曲线。结论药-时曲线显示，给药后0．5h房水中双氯芬酸胆碱滴眼液质量浓度达到峰值，12h基本代谢完全。该药显效快，并具有良好的角膜渗透性。     

Volume-localized two-dimensional correlated magnetic resonance spectroscopy of human breast cancer

A localized 2D correlation spectroscopic sequence (L-COSY) was implemented and applied in human breast cancer in vivo to evaluate the water to fat (both saturated and unsaturated) ratios and also to identify choline. Being in agreement with the conventional 1D magnetic resonance spectroscopy (MRS) results, elevated water to lipids ratios were found in breast cancers and choline was observed only in a few cancer patients.     

双波长薄层扫描法测定卵磷脂中磷脂酰胆碱的含量

目的：比较大豆、葵花和胡麻卵磷脂中磷脂酰胆碱的含量。方法：应用双波长薄层扫描法测定3种卵磷脂中磷脂酰胆碱的含量，以氯仿-甲醇-水(65：25：4，V：V：V)为展开系统，测定波长λs=235nm，参比波长λR=260nm．反射法双波长锯齿形扫描磷脂酰胆碱峰面积，外标两点法计算含量。结果：大豆、葵花和胡麻卵磷脂中磷脂酰胆碱的含量分别为64．6％、54．3％和62．4％。胡麻卵磷脂中磷脂酰胆碱的含量与大豆卵磷脂相似．略高于葵花卵磷脂。平均回收率为99．6％，RSD=3．12％。结论：用双波长薄层扫描法测定卵磷脂中磷脂酰胆碱的含量，方法经济实用，结果可靠。     

Septo-hippocampal and nBM-cortical cholinergic neurones exhibit differential time-courses of activation as a function of both type and duration of spatial memory testing in mice

We previously showed that the initial acquisition session of a spatial discrimination (mixed reference/working memory) test in an 8-arm radial maze induced differential activations in the ascending cholinergic septo-hippocampal and nBM-cortical pathways in mice. This data showed that the duration of post-test cholinergic activation was longer in the nBM-cortical pathway than in the septo-hippocampal projection. Moreover, the post-test durations but not the immediate post-test amplitudes of activation in each pathway decreased progressively as a function of repeated daily acquisition sessions. In the present study we have thus tested the hypotheses that the time-courses of post-test cholinergic activation in the septo-hippocampal and nBM-cortical pathways may vary both as a function of the type of memory used (working vs. reference) and according to the duration of repeated daily testing. Cholinergic activity in vivo in the hippocampus or frontal cortex of mice was quantified using measures of sodium-dependent high-affinity choline uptake at two different times (30 s and 15 min) following specific spatial working or reference memory testing in an 8-arm radial maze. The memory tests were administered daily over a 13-day period to attain high levels of performance in each type of task. In comparison to control groups both types of memory testing induced significant post-test cholinergic activations in each brain region on Day 15. However, cholinergic activity remained elevated in frontal cortex at 15 min post-test following reference memory testing, whereas significantly shorter durations of cortical and hippocampal cholinergic activation were observed following working memory testing using short (1 min) retention intervals. The possible significance of these differential modifications to the time-course of the post-test activations in these cholinergic pathways in working and reference memory processes and the putative transsynaptic mechanisms involved are discussed.     

Quantitative light microscopic autoradiography of [H]hemicholinium-3 binding sites in the rat central nervous system: a novel biochemical marker for mapping the distribution of cholinergic nerve terminals

The distribution of specific [³H]hemicholinium-3 ([³H]HC-3) binding sites throughout the rat forebrain was studied by means of quantitative light microscopic autoradiography. Tissue sections were labeled with 2.5 nM[³H]HC-3, apposed to tritium-sensitive film for 2 months and analyzed by computer-assisted densitometry. Regions of intense [³H]HC-3 labeling include the caudate-putamen, nucleus accumbens, olfactory tubercle, amygdala, habenula and the granule cell layer of the dentate gyrus. Little or no specific binding was detected in the corpus callosum, a white matter region. This distribution of specific [³H]HC-3 binding sites is compatible with a selective labeling of central cholinergic nerve terminals.     

Cholinergic innervation of the rat dentate gyrus: an immunocytochemical and electron microscopical study

Immunocytochemical studies using a monoclonal antibody to choline acetyltransferase (ChAT) were performed on sections of rat dentate gyrus. Light microscopical analysis of the immunoreactivity revealed dense fiber networks and many punctate structures predominantly located at the interface of the granule cell layer and molecular layer. In the elctron microscope, the immunostained punctate structures were identified as synaptic boutons which formed mainly symmetrical contacts onto dendritic elements. Few ChAT-immunoreactive boutons formed axosomatic contacts.     

Cholinergic somata and terminals in the rat substantia nigra: an immunocytochemical study with optical and electron microscopic techniques

The topographical distribution, histochemical characteristics, and anatomical relationships of the cellular elements containing choline acetyltransferase (ChAT) immunoreactivity, demonstrated with specific monoclonal antibodies to ChAT following the unlabelled antibody peroxidase-antiperoxidase (PAP) procedure at the optical and electron microscopic levels, were investigated in the rat substantia nigra (SN). Scarce, large (20-30 microns in maximum soma extent) cholinergic cell bodies and processes were found within the boundaries of the SN, in the borders of the pars compacta and pars reticulata, principally at caudal levels. Occasionally, cholinergic neurons were also found at intermediate levels of the SN, in the borders of the pars reticulata and pars lateralis. Cytologically, these large cells resembled ChAT-positive neurons localized in other areas of the central nervous system (CNS) of the rat--for example, the pontomesencephalotegmental (PMT) cholinergic complex (Ch5-Ch6) and the nucleus basalis of Meynert (nbM) (Ch4). Histochemically, ChAT-positive cells in the SN were characterized by their ability to utilize the reduced cofactor nicotinamide adenine dinucleotide phosphate (NADPH). Identified ChAT-positive neurons in the light microscope were subsequently studied in the electron microscope. All cholinergic neurons in the SN share essentially the same ultrastructural characteristics. The copious cytoplasm was rich in organelles with large lipofuscin granules. The synaptic input onto cell bodies and their dendrites was studied in serial sections. Synaptic contacts onto the perikarya and proximal dendrites were sparse and of asymmetric type. Both symmetric and asymmetric synaptic specializations onto ChAT-positive distal dendrites were detected. Asymmetric synaptic contacts onto cell bodies and dendrites were often defined by the presence of subjunctional dense bodies associated with the postsynaptic membrane. The pattern of the synaptic input to these cells differs strikingly from that onto unlabelled neighboring neurons. The perikarya and dendrites of the latter were characteristically covered with synaptic boutons. Scarce immunoreactive terminals in asymmetric synaptic contact with unlabelled dendritic profiles were also detected in portions of SN compacta with no ChAT-positive cells. Extranigrally located ChAT-positive cells of the PMT cholinergic complex were also examined in the electron microscope for comparison purposes. These cells exhibited, on the basis of their morphology and synaptic input pattern, very similar characteristics to those shown by SN cholinergic neurons.(ABSTRACT TRUNCATED AT 400 WORDS)     

Long-term effects of spinal transection of the development and function of sympathetic ganglia

The long-term effect of interruption of descending central pathways on the biochemical development and function of sympathetic neurons was examined in the sixth lumbar (L6) sympathetic ganglia of the rat. Previous investigations had defined the normal maturation of presynaptic choline acetyltransferase (CAT) activity, postsynaptic tyrosine hydroxylase (T-OH) activity and total protein in L6 ganglia. Neonatal spinal cord transection prevented the normal ontogeny of CAT activity: enzyme activity was 40% of control one week and one year after surgery. Similarly, T-OH activity failed to develop normally after transection and was 22% of control one year postoperatively. Spinal transection at 30 days of age did not alter baseline CAT or T-OH activities in L6 ganglia when examined up to 6 months after surgery. Apparently during the first month of life descending central pathways exert critical facilitatory influences on sympathetic ganglia maturation; interruption of these influences results in long-lasting biochemical deficits. We also examined the role of central mechanisms in adult sympathetic function. Stressful stimuli, including reserpine treatment, normally induce adult T-OH through reflex sympathetic activation. This biochemical adaptability was studied by treating rats with reserpine after spinal transection. After motor and autonomic spinal reflexes returned in paraplegic animals, reserpine treatment was initiated. Spinal animals did not exhibit T-OH induction. These observations indicate that central rather than spinal mechanisms govern this biochemical adaptability of mature sympathetic neurons.     

The effects of blepharorrhaphy induced depression of corneal cholinergic activity

Unilateral lid closure for 8 or more days had previously been shown to reduce rabbit corneal epithelial choline acetyltransferase (ChAc) activity without affecting lactic dehydrogenase activity or thymidine, uridine, leucine and alanine incorporation rates. In the present study, the reduction in ChAc activity was found to be associated with a similar reduction in acetylcholine (ACh) content, to a mean value of 16 and 17%, respectively, of control eye levels. However, on reopening the lids, ACh levels recovered much more rapidly, achieving a mean value 67% of control values (P > 0·05) in 48 hr while ChAc activity was only 23% of control eye levels at 48 hr and required more than 30 days to fully recover.Unilateral lid closure of 10 days was also associated with a small increase in corneal thickness, 0·46±0·09 mm vs. 0·41±0·04 mm (P < 0·05), and reductions in standing electrical potential, 5·5±7·8 mV vs. 13·2±15·2 mV (P < 0·05), and short circuit current, 2·7±2·6 μA vs. 4·9±3·5 μA (P < 0·05). On re-opening the lids, the short-circuit current recovered within 24 hr, the corneal thickness within 3 days and the resting potential within 4 days. Administration of ACh 10^?4m, pilocarpine 10^?4m, eserine 10^?6m or carbachol 10^?5m to the epithelial side of corneas mounted in chambers immediately after reopening the lids failed to elevate either the standing electrical potentials or short-circuit currents; a causal relationship between cholinergic activity and corneal electrical phenomena could not be demonstrated.     

Autoimmune neuromuscular disease induced by a preparation of choline acetyltransferase

An apparent fatal autoimmune disease was induced in guinea pigs by injection of a preparation of choline acetyltransferase in complete Freund's adjuvant. The animals probably died from respiratory failure based on the evidence from clinical, histological, and histochemical examination. At autopsy the pathogenic lesions were located at the neuromuscular junctions and near the nerves where choline actyltransferase was found. It is further proposed that this is a presynaptic autoimmune neuromuscular disease based on the finding of numerous target, as well as targetoid, fibers in muscle after histochemical staining. There was also denervation shown by electromyographic measurements in the form of positive sharp waves as well as fibrillation discharges.