Guanosine 3',5'-monophosphate in sympathetic ganglia: increase assoicated with synaptic transmission

Brief stimulation of cholinergic preganglionic nerve fibers resulted in an increase in guanosine 3',5'-monophosphate (cyclic GMP) in the bullfrog sympathetic ganglion. When the release of synaptic transmitter was prevented by a high-magnesium, low-calcium Ringer solution, stimulation of preganglionic nerve fibers did not increase cyclic GMP in the ganglion. The increase in cyclic GMP caused by preganglionic stimulation was also blocked by the muscarinic antagonist, atropine. The data indicate that the increase in cyclic GMP is associated with synaptic transmission and support the possibility that cyclic GMP may mediate the postsynaptic action of acetylcholine at muscarinic cholinergic synapses.     

Nicotinic antagonists enhance process outgrowth by rat retinal ganglion cells in culture

Functional nicotinic cholinergic receptors are found on mammalian retinal ganglion cell neurons in culture. The neurotransmitter acetylcholine (ACh) can be detected in the medium of many of these retinal cultures, after release presumably from the choline acetyltransferase-positive amacrine cells. The postsynaptic effect of endogenous or applied ACh on the ganglion cells can be blocked with specific nicotinic antagonists. Here it is shown that within 24 hours of producing such a pharmacologic blockade, the retinal ganglion cells begin to sprout or regenerate neuronal processes. Thus, the growth-enhancing effect of nicotinic antagonists may be due to the removal of inhibition to growth by tonic levels of ACh present in the culture medium. Since there is a spontaneous leak of ACh in the intact retina, the effects of nicotinic cholinergic drugs on process outgrowth in culture may reflect a normal control mechanism for growth or regeneration of retinal ganglion cell processes that is exerted by ACh in vivo.     

柄海鞘神经复合体的显微观察

采用甲苯胺蓝染色和Golgi镀银法对柄海鞘神经复合体的结构进行显微观察,并通过免疫组织化学方法对甲硫氨酸脑啡肽在神经复合体中的分布进行了研究。①甲苯胺蓝染色法显示,神经复合体由神经节、神经腺和疏松结缔组织组成;神经节分为皮质部、髓质部和过渡带;神经腺位于神经节背侧面,由腺小叶组成;神经细胞呈深蓝色,神经纤维呈浅蓝色,与背景反差较大。Golgi镀银法显示的结果不理想,神经细胞和神经纤维着色不明显。②免疫组化结果显示,M-ENK在神经复合体中分布广泛,神经细胞、神经纤维及上皮细胞均有Met-ENK阳性反应。     

Junctional physiology and motor nerve distribution in the fast adductor muscle of the scallop

Electrical recordings from single muscle cells in the fast portion of the scallop adductor have revealed a multiterminal distribution of motor nerves. All motor junctions appear to be of the fast designation, and several nerve fibers supply each muscle cell. The muscle fibers, by virtue of common innervation, are grouped into functional motor units. The pattern of innervation in scallops thus shares functional similarities with the motor distribution to skeletal muscle fibers of both vertebrates and arthopods.     

狗肾脏交感节后纤维来源的研究

采用辣根过氧化物酶逆行追踪技术(HRP技术)将CB_HRP注入狗的一侧肾脏,对8只狗肾脏交感节后纤维来源进行了研究.结果表明:交感节后神经元标记细胞分布于注射侧T6~L3节段交感干神经节,高峰节段为T12~L2节段,8例共见标记细胞7 077个,占交感干神经节内标记细胞总数90.86%.在注射侧腹腔神经节、肠系膜前神经节和主动脉肾神经节也见有大量交感节后神经元标记细胞.标记细胞以梭形、卵圆形和多极的中小型细胞为主,交感干神经节内标记细胞靠边缘分布,而其它部位则均匀、散在分布.说明狗肾脏交感节后纤维来源广泛.     

Bilateral symmetry and interneuronal organization in the buccal ganglia of Aplysia

Principles of functional organization of the bilaterally symmetric buccal ganglia of Aplysia were studied in 20 identified cells used as a reference population. Four of the identified cells (two in each ganglion) are multiaction interneurons, each of which innervates six identified ipsilateral follower cells, mediating cholinergic excitation to one cell and cholinergic inhibition to five others. Bilateral coordination is effected by common inputs to all four interneurons. Ipsilateral pairs of interneurons are electrotonically coupled and produce identical synaptic actions on their common follower population. This apparent redundancy of interneuronal action leads to feed-forward summation, eliciting amplified synaptic output from each interneuron pair.     

Geometrical differences among homologous neurons in mammals

The dendritic arbors of sympathetic neurons in different species of mammals vary systematically: the superior cervical ganglion cells of smaller mammals have fewer and less extensive dendrites than the homologous neurons in larger animals. This difference in dendritic complexity according to body size is reflected in the convergence of ganglionic innervation; the ganglion cells of progressively larger mammals are innervated by progressively more axons. These relations have implications both for the function of homologous neural systems in animals of different sizes and for the regulation of neuronal geometry during development.     

Synaptic connections of the centrifugal fibers in the pigeon retina

The centrifugal fibers in the pigeon retina end in the inner nuclear layer and form two kinds of terminals, convergent and divergent. In the inner nuclear layer the fibers synapse with amnacrine and displaced ganglion cells. Because of their great number and their even distribution these fibers appear to constitute a system for the localized centrifugal control of the retinal functions.     

Neurons: secretory activity during limb regeneration and induction in the newt

Material staining with aldehyde fuchsin appeared in sensory ganglion cells supplying a regenerating limb or nerve-induced blastema and in regenerating nerve fibers within the blastema. With the electron microscope, large (1000 to 2500 angstroms), dense granules were observed in the perikarya and within end bulbs of peripheral nerves. Secretory materials may be elaborated and transported by neurons during limb regeneration and induction in the newt.     

Photoreception in a barnacle: electrophysiology of the shadow reflex pathway in Balanus cariosus

The photoreceptors in the median ocellus of the rock barnacle depolarize when illuminated. This depolarization spreads passively to the axon terminals in the supraesophageal ganglion. A small number of cells in the supraesophageal ganglion hyperpolarize when the median ocellus is illuminated and depolarize when it is shadowed. Nerve impulses are superimposed on the slow depolarization of the ganglion cells. Impulse activity in response to shadowing the median ocellus is recorded in a few fibers of the circumesophageal connectives. Picrotoxin blocks this shadow-induced activity. A model of the shadow reflex pathway is presented.     

Unusual retinal cells in the dolphin eye

By comparison to the cellular constituents of the retinas of certain other diving mammals, the elements of the dolphin retina include an unusually large number of specialized cells. Both cone and rod receptors may be identified. An unusual amacrine cell may be seen which produces a process that spans the cells between the inner plexiform and outer plexiform layers. Most unusual is a layer of giant ganglion cells which appears to serve most of the central retina. The giant ganglion cells support giant dendrites and optic nerve fibers which range up to 8 micrometers in diameter.     

Parasympathetic innervation maintains epithelial progenitor cells during salivary organogenesis

The maintenance of a progenitor cell population as a reservoir of undifferentiated cells is required for organ development and regeneration. However, the mechanisms by which epithelial progenitor cells are maintained during organogenesis are poorly understood. We report that removal of the parasympathetic ganglion in mouse explant organ culture decreased the number and morphogenesis of keratin 5-positive epithelial progenitor cells. These effects were rescued with an acetylcholine analog. We demonstrate that acetylcholine signaling, via the muscarinic M1 receptor and epidermal growth factor receptor, increased epithelial morphogenesis and proliferation of the keratin 5-positive progenitor cells. Parasympathetic innervation maintained the epithelial progenitor cell population in an undifferentiated state, which was required for organogenesis. This mechanism for epithelial progenitor cell maintenance may be targeted for organ repair or regeneration.     

牛胃植物性神经的分布研究（Ⅰ）──付交感神经的分布

本文以黄牛为实验对象,采用大体解剖学方法对成年健康黄牛雌雄各一头进行了其胃脏上神经分布的追踪研究,描述记录付交感神经－－迷走神经食管背腹二干的详细分支情况。其结果为：（１）腹干分支干要有：网胃丛支、网－－瓣丛支、瓣胃丛支及皱胃丛支四支,且都进一步分布数小支进入胃壁内。（２）背干分支主要有左、右二大支,其中左支较大,右支较小。左支又分成前庭背囊丛支、腹腔丛支和瘤胃右支三支;右支分成腹腔丛支和网、瓣胃支二支。（３）分布特点是腹干多分布于网、瓣、皱胃;其中以网瓣皱胃壁面及其三个胃室交界处的分大数量大,密集,并多以“袢”状和一侧性“梳”状结构分出。     

支配山羊胸腺的神经纤维起源

用ＨＲＰ法研究证明,支配山羊胸腺的初级传入神经来源于双侧Ｃ１～Ｔ５ 脊神经节,以同侧为主;其标记神经元的分布呈双峰型;在双侧结状节也出现少量标记细胞,山羊胸腺的感觉经两侧神经传入,以交感途径占优势;交感节后纤维来自双侧颈前节、颈中节、星状节及Ｔ２～Ｔ５ 椎旁节,其中颈中节和星状节的标记细胞最多;在双侧Ｃ１～２节脊髓腹角和延髓疑核出现标记细胞较多,延髓迷走神经背核、面后核和脊上核出现较少的标记细胞。     

Giant Muscle Fibers in a Barnacle, Balanus nubilus Darwin

Cross-striated muscle fibers of very large size have been found in the scutal-tergal adductor and depressor muscles of the large barnacle B. nubilus. Adductor muscle fibers are up to 2 mm thick. They are innervated by separate nerves, each supplying one end, but not the central region, with terminals; each fiber receives two or three excitor axons. Depressor muscle fibers are up to 1.4 mm thick and receive multiterminal innervation along their entire length; they are innervated by two excitor axons. Postsynaptic potentials are of small or large size and lead to small or large twitches; they do not show facilitation. The muscle fibers shorten to as little as one-sixth resting length.     

山羊感觉和交感神经节中的肽类免疫反应结构

所有背根节和迷走神经结状节出现大量P物质(SP)阳性胞体和纤维,小细胞占92％,大中型细胞占8％,仅有极少数生长抑素(SS)样神经胞体。大量含SP的纤维和终未见于颈上节和腹腔-前肠系膜神经节,但含SS的纤维和终末主要见于腹腔-前肠系膜神经节,颈上节甚少。交感节中无SP和SS阳性胞体。出现于交感神经节中的SP和SS纤维和终末,可能来自背根节初级感觉神经元的外周侧支或肠神经元。按照这个模式,SP和SS可通过不涉及中枢神经系统的外周短反射环路;去调节交感神经的反应。     

Newly found action of cocaine

Cocaine augments appreciably the effects of small doses of acetylcholine on the heart rate, blood pressure, and the nictitating membrane in intact, anesthetized animals. This phenomenon assigns cocaine, thus far only known as a potentiator of adrenergic stimulation, a more general role of potentiator of both adrenergic and cholinergic neurohumors.     

Immunocytochemical detection of acetylcholine in the rat central nervous system

A specific antibody to acetylcholine was raised and used as a marker for cholinergic neurons in the rat central nervous system. The acetylcholine conjugate was obtained by a two-step immunogen synthesis procedure. An enzyme-linked immunosorbent assay was used to test the specificity and affinity of the antibody in vitro; the results indicated high affinity. A chemical perfusion mixture of allyl alcohol and glutaraldehyde was used to fix the acetylcholine in the nervous tissue. Peroxidase-antiperoxidase immunocytochemistry showed many acetylcholine-immunoreactive cells and fibers in sections from the medial septum region.     

Distribution of ChAT in the Diencephalon of the One Day Chicken

The distribution of choline-acetyltransferase(ChAT)-like immunoreactive structure in the one day chicken diencephalons was examined by the method of streptavidin-Perosidase(SP)immunocytochemistry.It was found that ChAT immunoreactive neurons and fibers presented in many regions of one day chicken.Neural structure containing cholinergic neurons with varying density and immunoreactivity were the N.habexularis lateralis and N.habexularis medialis of the epithalamus,the N.rotundus,N.Ovoidalis,N.subrotundus and N.geniculatus lateralis of the thalamus,the hypothalamus,the N.decussationis supraopticae dorsalis of stratathalamus.There were also many varicose and nonvaricose fibers and terminals in the N.geniculatus lateralis and the hypothalamus.The results suggested that the diencephalons of one day chicken is richly innervated by the cholinergic neuron system.     

Ontogeny of adrenergic arousal and cholinergic inhibitory mechanisms in the rat

With spontaneous activity as a measure of arousal, dose response curves were established for scopolamine and amphetamine administered to 10-, 15-, 20-, 25-, and 100-day-old rats. Amphetamine always increased activity, but scopolamine had no efect on younger rats, which suggests that adrenergic excitatory areas in the brainstem mature more rapidly than cholinergic inhibitory areas in the forebrain.