Pituitary Adenylate Cyclase-Activating Polypeptide (PACAP) Regulation of Sympathetic Neuron Neuropeptide Y and Catecholamine Expression

Abstract: Two forms of pituitary adenylate cyclase-activating polypeptide (PACAP), the 38- and 27-amino-acid forms (PACAP38 and PACAP27, respectively), which share amino acid sequence homology with vasoactive intestinal peptide (VIP), were evaluated for their abilities to regulate sympathetic neuron catecholamine and neuropeptide Y (NPY) expression. PACAP38 and PACAP27 potently and efficaciously stimulated NPY and catecholamine secretion in primary cultured superior cervical ganglion (SCG) neurons; 100- to 1,000-fold higher concentrations of VIP were required to modulate secretion, suggesting that SCG neurons express the PACAP-selective type I receptor. PACAP38 elicited a sustained seven- to ninefold increase in the rate of NPY secretion and three-fold stimulation in the rate of catecholamine release. PACAP38 and PACAP27 produced parallel neuronal NPY and catecholamine release, but cellular levels of NPY and catecholamines were differentially regulated. Sympathetic neuron NPY content was decreased, whereas cellular total catecholamine levels were elevated by the PACAP peptides; total NPY and catecholamine levels (secreted plus cellular content) were increased. In concert with the increased total peptide and transmitter production, pro-NPY and tyrosine hydroxylase mRNA levels were elevated. Furthermore, PACAP38 was more efficacious than PACAP27 in regulating pro-NPY and tyrosine hydroxylase mRNA. SCG neuronal expression of mRNA encoding the type I PACAP receptor further supported the studies demonstrating that sympathetic neuronal levels of NPY and catecholamine content and secretion and mRNA are differentially regulated by the PACAP peptides.     

Evidence for Glutamatergic Projections from the Cochlear Nucleus to the Superior Olive and the Ventral Nucleus of the Lateral Lemniscus

Abstract: This study attempts to determine if projections ascending from the guinea pig cochlear nucleus (CN) could be glutamatergic and/or aspartatergic. Multiple radio frequency lesions were made to ablate the right CN. The ablation was verified histologically. To identify the principal targets of CN efferents, silver impregnation methods were used to localize the preterminal degeneration of fibers in transverse sections of the brainstem 5 and 7 days after CN ablation. CN efferents projected heavily to the lateral superior olive (LSO) ipsilaterally, the medial superior olive (MSO) bilaterally, and contralaterally to the medial (MNTB) and ventral (VNTB) nuclei of the trapezoid body, the ventral (VNLL) and intermediate nuclei of the lateral lemniscus and the central nucleus of the inferior colliculus (ICc). There were smaller projections to the lateral nucleus of the trapezoid body ipsilaterally, the dorsal and dorsomedial periolivary nuclei bilaterally, and the dorsal nucleus of the lateral lemniscus contralaterally. There were sparse projections to the VNLL and ICc ipsilaterally and the CN contralaterally, and a very sparse projection to the contralateral LSO. To determine if CN efferents were glutamatergic and/or aspartatergic, the fresh brainstem was sectioned transversely and samples of the LSO, MSO, MNTB, VNLL, and ICc were taken to measure the electrically evoked release and the uptake of d -[³H]Asp and [¹⁴C]Gly or [¹⁴C]GABA 3–5 days after the CN ablation. The release studies suggest that only certain of the histologically identified projections ascending from the CN may be glutamatergic and/or aspartatergic. CN ablation depressed d -[³H]Asp release in the MSO bilaterally and in the contralateral MNTB and VNLL, suggesting that the CN efferents to these nuclei may use glutamate or aspartate as a transmitter. It was unclear whether a marginal depression of d -[³H]Asp release in the ipsilateral LSO reflected the presence of glutamatergic CN projections to this nucleus. d -[³H]Asp release in the ICc was unaffected, suggesting that CN efferents to this nucleus may not be glutamatergic. There were no deficits in d -[³H]Asp uptake. [¹⁴C]Gly release from the LSO and MSO was unchanged. [¹⁴C]Gly uptake was unchanged in the MSO and depressed only in the contralateral LSO, possibly reflecting subnormal uptake activity in endings contributed by contralateral MNTB cells that had lost their CN efferents. [¹⁴C]GABA uptake in the MNTB, VNLL, and ICc was unchanged. [¹⁴C]GABA release was unchanged in the VNLL and ICc. [¹⁴C]GABA release was depressed only in the contralateral MNTB, possibly reflecting the loss of a small complement of GABAergic CN efferents and the reaction of GABAergic projections from the contralateral VNTB to their loss of CN efferents.     

Bifurcation, Bursting, and Spike Frequency Adaptation

Many neural systems display adaptive properties that occur on timescales that are slower than the time scales associated withrepetitive firing of action potentials or bursting oscillations. Spike frequency adaptation is the name givento processes thatreduce the frequency of rhythmic tonic firing of action potentials,sometimes leading to the termination of spiking and the cell becomingquiescent. This article examines these processes mathematically,within the context of singularly perturbed dynamical systems.We place emphasis on the lengths of successive interspikeintervals during adaptation. Two different bifurcation mechanisms insingularly perturbed systems that correspond to the termination offiring are distinguished by the rate at which interspike intervalsslow near the termination of firing. We compare theoreticalpredictions to measurement of spike frequency adaptation in a modelof the LP cell of the lobster stomatogastric ganglion.     

Cervex brush versus vaginal–cervical–endocervical (VCE) triple smear techniques in cervical sampling

Cervex brush versus vaginal–cervical–endocervical (VCE) triple smear techniques in cervical sampling
Cervex brush sampling was compared with the conventional triple vaginal–cervical–endocervical (VCE) smear technique. Nine hundred and fifty‐nine Cervex brush smears and 1064 VCE smears were studied. All smears with both methods were technically satisfactory for evaluation. Endocervical cells were found in 90.7% and metaplastic cells in 73.3% of Cervex brush samples and in 92.5% and 64.1% of VCE samples, respectively. There were significantly more metaplastic cells in smears from premenopausal women. Low grade squamous intraepithelial lesion (SIL) was found in three Cervex brush samples and in two VCE samples. High‐grade SIL was found only in one Cervex brush sample. Benign cellular changes were found in 142 Cervex brush samples and in 144 VCE samples. Sampling with the Cervex brush is efficient, simple and fast and gives high quality cervical smears for cytological evaluation.     

Demonstration of retinal afferents in the RCS rat,with reference to the retinohypothalamic projection and suprachiasmatic nucleus

In the Royal College of Surgeons (RCS) rat, characterized by inherited retinal dystrophy, retinal projections to the brain were studied using anterograde neuronal transport of cholera toxin B subunit upon injection into one eye. The respective immunoreactivity was found predominantly contralateral to the injection site in the lateral geniculate nucleus, superior colliculus, nucleus of the optic tract, medial terminal nucleus of the accessory optic tract, and bilateral hypothalamic suprachiasmatic nuclei. Although terminal density was somewhat reduced in dystrophic rats, the projection patterns in these animals appeared similar to those seen in their congenic controls and were comparable to the visual pathways described for the rat previously. In dystrophic rats, the number of cell bodies exhibiting immunoreactivity to vasoactive intestinal polypeptide, viz. a population of suprachiasmatic neurons receiving major retinohypothalamic input, was reduced by one-third, and some differences were observed in the termination pattern of the geniculohypothalamic tract, as revealed by immunoreactivity to neuropeptide Y in the suprachiasmatic nucleus.This study was supported by grants from the DFG (Re 644/2-1) and the NMFZ, Mainz (to S.R.).     

大鼠颈上神经节烟碱电流的整流及失敏

在培养的新生大鼠颈上神经节交感神经元标本上,用全细胞膜片钳技术研究了烟碱型乙酰胆碱受体（ｎＡＣｈＲ）通道的整流及失敏现象。烟碱激动剂引起的全细胞电流在膜电位为负值时随膜电位呈线性改变,而在膜电位达＋６０ｍＶ时仍不出现外向电流,表现出强烈的内向整流。ｎＡＣｈＲ通道电流存在失敏现象,即持续恒压喷射激动剂所引起的全细胞电流随时间呈指数衰减,不能保持在峰值水平,失敏随激剂浓度呈量效关系,膜电位的超极化也加     

The paramedial neurosecretory cells of the suboesophageal ganglion of the cricket,Teleogryllus commodus (Walk.)

Summary Ovariectomy, performed immediately after the final hatch, caused a reduction of stainable (neurosecretory?) material in the paramedial neurosecretory cells (PNC) (A-type) of the suboesophageal ganglion in 10 day-old females of Teleogryllus commodus (Walk.). A concomitant increase in nuclear volume and in the incorporation of ³⁵S-cysteine indicates increased synthesis of neurosecretory material. From these findings it is concluded that more stainable material is secreted in the cerebral neurohaemal organ after Ovariectomy. A functional relationship between the PNC and the ovaries is suggested.     

Origin,destination and mapping of tritocerebral neurons of locust

Summary The connectivities of the tritocerebrum of locust (Locusta migratoria L., Schistocerca gregaria (Forsk.)) were studied histologically and by means of cobalt chloride infusion. Its neuropil consists partly of fibers which traverse the tritocerebrum and areas consisting of neuropilar agglomerizations (glomeruli). The following direct connections between the tritocerebrum and other regions were observed: connections to 1) dorsal and lateral brain regions (mushroom body, optic lobe), 2) the ventral nerve cord, 3) the stomatogastric nervous system (here the protocerebrum and the subesophageal ganglion are also involved in these connections), 4) the retro-cerebral glands (corpora cardiaca, corpora allata), and 5) muscles of the foregut. Acknowledgements. This study was supported by grants from the Deutsche Forschungsgemeinschaft to N.K. The authors wish to thank Dr. H.-W. Honegger (Fachbereich Biologie, Universität Konstanz) and Dr. N.J. Strausfeld (E.M.B.L., Heidelberg) for helpful comments and for assisting with the English text     

菌种与品种最佳组合的选育及增产效果

本文通过多年多点的田间接种试验,分析了大豆根瘤菌C_(33)(系VSDA_(110)的突变株)的增产效应.在合丰25号大豆接种C_(33)取得明显的增产效果,两年平均比CK增产28.55%,比61A76增产24.5%;C_(33)接种在其他品种以及在不同类型和肥力的土壤上增产效果也均高于CK和61A76,说明大豆根瘤菌C_(33)比当前生产上应用的61A76更具有广谱性和高效性.     

Mechanism of Neurotransmitter Release Elicited by the Preferential α1-Adrenergic Receptor Agonist Phenylephrine in Superfused Superior Cervical Ganglion Cells in Culture

Phenylephrine increased [3H]norepinephrine efflux and accumulation of cyclic AMP in cultured rat superior cervical ganglion cells superfused with Tyrode's solution. The purpose of this study was to determine the mechanism and relationship between these two events. Electrical stimulation (1-2 Hz), potassium chloride (50 mM), and the preferential alpha 1-adrenergic receptor agonist phenylephrine (1-100 microM) increased fractional tritium efflux, whereas methoxamine, cirazoline, and amidephrine were relatively ineffective. Phenylephrine, but not methoxamine and cirazoline, also increased cyclic AMP accumulation. Phenylephrine-induced tritium efflux was not altered by alpha- and beta-adrenergic receptor antagonists or by removal of extracellular calcium. Phenylephrine-induced cyclic AMP accumulation was blocked by the beta-adrenergic receptor antagonists propranolol and atenolol. Forskolin (10 microM) and the nonhydrolyzable cyclic AMP analogue 8-(4-chlorophenylthio)cyclic AMP (100 microM) had minimal effect on tritium efflux. However, phenylephrine-evoked increase in tritium efflux was dose dependently attenuated by the neuronal uptake blocker cocaine, and phenylephrine dose-dependently inhibited the incorporation of [3H]norepinephrine into neuronal stores. We conclude that the increase in tritium efflux induced by phenylephrine is independent of cyclic AMP accumulation and appears to be mediated by uptake of phenylephrine via the neuronal carrier-mediated amine transport process, which in turn promotes efflux of the adrenergic transmitter from its storage sites.