Types of nerves in the enteric nervous system

The enteric nervous system is one of the three divisions of the autonomic nervous system, the others being the sympathetic and parasympathetic. In contrast to the other divisions, it can perform many functions independently of the central nervous system. It consists of ganglionated plexuses, their connections with each other, and nerve fibres which arise from the plexuses and supply the muscle, blood vessels and mucosa of the gastrointestinal tract. The enteric nervous system contains a large number of neurons, approximately 10⁷ to 10⁸. About ten or more distinct types of enteric neurons have been distinguished on electrical, pharmacological, histochemical, biochemical and ultrastructural grounds as well as on the basis of their modes of action. Both excitatory and inhibitory nerves supply the muscle and there are inhibitory and excitatory interneurons within the enteric plexuses. There are also enteric nerves which supply intestinal glands and blood vessels, but these receive less emphasis in this commentary.Correlations between groups of neurons defined on different criteria are poor and in many cases the physiological roles of the nerves are not known. The functions of noradrenergic nerves which are of extrinsic origin are reasonably well understood, but cholinergic nerves in the intestine are the only intrinsic nerves for which both the transmitter and to some extent the functions are known. In the case of non-cholinergic, non-noradrenergic enteric inhibitory nerves, the functions are understood but the transmitter is yet to be determined, both adenosine 5′-triphosphate and vasoactive intestinal polypeptide having been proposed. Other nerves have been defined pharmacologically (non-cholinergic excitatory nerves to neurons and muscle, intrinsic inhibitory inputs to neurons, and enteric, non-cholinergic vasodilator nerves) and histochemically (intrinsic amine-handling neurons and separate neurons containing peptides: substance P, somatostatin, enkephalins, vasoactive intestinal polypeptide, gastrin cholecystokinin tetrapeptide, bombesin, neurotensin and probably other peptides). Little is known of the functions of these nerves, although a number of proposals which have been made are discussed.     

Forebrain and lower brainstem participation in facilitatory and inhibitory regulation of the display of lordosis in female rats

Neural transection of the dorsal extrahypothalamic descending afferents by means of an L-shaped Halász knife at the anterior commissure (anterior roof deafferentation. ARD) markedly potentiated the display of lordosis and soliciting behaviors. Bilateral lesions of the ventromedial hypothalamus (VMH) attenuated lordotic activity in the ARD sham females but not in the ARD females. In contrast, the lesions in the pontine central gray concurrently with ARD effectively inhibited the display of lordosis but not soliciting behaviors. These results suggest that the VMH may not be a primary focus of the dorsal extrahypothalamic inhibitory influence on lordosis. The influence of this inhibitory system seems to be dominant in regulating the expression of lordosis behavior, compared to that of the hypothalamic lordosis facilitating system. Furthermore, the dorsal extrahypothalamic inhibitors influence which could be removed by ARD must be modified by the neural mechanism in the lower brain stem in which the pontine central gray may be actively involved.     

Detection of radiolabelled bone marrow cells bearing surface ace immunoglobulins by combined autoradiography and immunoperoxidase

A method is described for the simultaneous detection of radiolabelled bone marrow cells bearing surface immunoglobulins by combined autoradiography and immunoperoxidase. Bone marrow cells from normal CBA mice prelabelled in vivo with ¹²⁵IUDR or exposed in vitro to [³H]thymidine were incubated with rabbit anti-mouse immunoglobulins under capping conditions, washed, cytocentrifuged and treated with methanol and hydrogen peroxide to destroy endogenous peroxidase. Cells were then covered with peroxidase-conjugated goat anti-rabbit immunoglobulins, washed, treated with diaminobenzidine a and hydrogen peroxide and finally covered with autoradiographic stripping film and exposed for different times. Peroxidase-positive cells were typically capped and those radiolabelled had autoradiographic silver grains overlying the nucleus.     

Effects of potassium chloride on sexual behavior and the cortical EEG in the ovariectomized rat

The facilitation of lordosis behavior by the cortical application of KCl has been confirmed. Ovariectomized female rats were injected with estradiol benzoate (EB) for 3 days and then a 15% KCl solution was put into permanent cannulae resting on the cortical dura. Sexual behavior tests were performed 15, 30, 60 and 90 min and 24 hr after KCl application and a lordosis quotient (LQ) was obtained from each 10-mount test. There was a significant increase in the LQ 15 min after KCl application to levels which approached those seen after priming with both EB and progesterone. Although lordosis behavior was facilitated, no EEG changes were found following KCl application in 7 of 9 rats, but there was marked depression of the amplitude of the cortical EEG in the remaining 2. It is concluded that KCl application, a treatment which produces functional decortication by inducing spreading depression, suppresses a cortical inhibitory system for lordosis behavior.     

Technical improvements in the clotted plasma droplet MIF assay in vitro.

The migration inhibitory activity of culture supernatants of rat and human lymphocytes stimulated with PHA and Con A-Sepharose was tested on cell migration from clotted plasma droplets. This technique was improved by using homologous as well as heterologous plasma and fibrinogen solutions for suspending the migratory cells, automatic micropipettes for performing the technique and purified cell populations as target. The effects of calcium chloride and of the cell concentration in the plasma droplets on the migration indices obtained in the MIF assay were tested.     

糖尿病大鼠视网膜基因表达谱差异的初步分析

目的 建立大鼠正常视网膜和糖尿病8周视网膜基因表达谱，比较两者差异，初步分析糖尿病视网膜病变的相关基因。方法 通过限制片段差异显示 PCR（ restriction fragments differential display-PCR，RFDD-PCR）获得正常大鼠视网膜及8周糖尿病大鼠视网膜组织转录组片段。应用Fraent Analysis等软件，对差异片段进行生物信息学分析，初步确定糖尿病视网膜病变相关基因／表达序列标签（ expression sequence tag, Ksr）。结果 获得有意义的片段共3639个，有差异的片段840个，占表达数的23．08％。其中包括5个视觉传导相关基因，13个兴奋性神经递质受体基因和3个抑制性神经递质受体基因。糖尿病8周大鼠视网膜Rhodopsin kinase,β-arrestin,Phosducin, rod photoreceptor cGMP-gated channel 和 Rpe65的表达下调，离子型谷氨酸受体iGluR1-4下调，代谢性谷氨酸受体及γ-氨基丁酸受体各亚型则普遍上调，而甘氨酸受体表达无变化。结论 糖尿病8周大鼠神经视网膜已受到累及，其基因表达模式的改变，可能与糖尿病早期视功能损害有关。     

HLA-C revisited

During the past 10 years knowledge about the interactions between major histocompatibility complex (MHC) class I molecules and the T-cell receptor (TCR) complex of cytotoxic T-cells (CTL) has developed dramatically. But the primary interest, both with respect to structure as well as function, has concentrated on HLA-A and -B molecules because of their high sequence polymorphism and their dominating presence at the cell surface. In contrast, HLA-C molecules seemed to be of only minor importance in the cascade of immune reactions owing to their more limited polymorphism and reduced levels of surface expression. The inability to define a number of antigen specificities had the result that HLA-C molecules were often neglected in studies of immune response, transplantation, and disease association. More recently a new function has been identified for HLA class I molecules where they act as inhibitors of the lytic capacity of natural killer (NK) cells and non-MHC-restricted T-cells. Moreover, the understanding of this novel mode of negative regulation of cytotoxicity was remarkably influenced by HLA-C since these were the first HLA class I molecules found to have such inhibitory potential. With this new inhibitory function serving as an essential component of the immune system, HLA-C molecules can no longer be neglected.     

Effect of epitalon on the lifespan increase in Drosophila melanogaster

The geroprotector activity of epitalon, a synthetic tetrapeptide Ala–Glu–Asp–Gly, was studied on the Drosophila melanogaster wild strain Canton-S. The substance was added to the culture medium only at the developmental stage (from egg to larva). Epitalon significantly increased the lifespan (LS) of imagoes by 11–16% when applied at unprecedented low concentrations — from 0.001×10^–6 to 5×10^–6 wt.% of culture medium for males and from 0.01×10^–6 to 0.1×10^–6 wt.% of culture medium for females. The increase in LS did not depend on the substance dose. Effective concentrations of epitalon were 16 000–80 000 000 times lower than those of melatonin. The possible mechanisms of the antioxidant and regulatory effects of epitalon are discussed.