Generation of adrenergic and cholinergic potentials in sympathetic ganglion cells

Norepinephrine elicited a hyperpolarizing response, and acetylcholine (during nicotinic blockade) elicited a depolarizing one. Both responses showed no increase in membrane conductance. The norepinephrine response was suppressed by initial depolarization; the acetylcholine response (frog cells); by hyperpolarization. These neurotransmitters apparently can activate electrogenic mechanisms which do not involve movement of ions down their electrochemical gradients.     

Supraoptic neurosecretory cells: adrenergic and cholinergic sensitivity

Adrenergic and cholinergic agonists and antagonists were applied microelectrophoretically to over 700 neurons in the cat supraoptic nucleus, 20 percent of which were antidromically identified as neurosecretory cells. Norepinephrine uniformly depressed all sensitive cells. Acetylcholine caused both muscarinic depression and nicotinic excitation which were antagonized by atropine and dihydro-beta-erythroidine, respectively. These results support the hypothesis that norepinephrine and acetylcholine are directly involved in controlling the release of antidiuretic hormone.     

Ionic mechanisms of cholinergic excitation in molluscan neurons

Acetylcholine appears to be an excitatory transmitter at synapses on two different types of molluscan nerve cells: the so-called D- and CILDA neurons. The action of this substance is different in the two cases. In D-neurons, this compound increases the permeability of the subsynaptic or somatic membrane to chloride ions, and through a net efflux of this anion, depolarizes the cell. In CILDA neurons, on the other hand, acetylcholine depolarzies the cell by increasing its permeability to sodium ions.     

Localization of the adrenergic feeding system in the rat diencephalon

Injection of 6 micrograms of aqueous norepinephrine elicits eating only when it takes place at sites within a limited region of the rat brain. The distribution of effective sites coincides with that of systems connected to an extrahypothalamic pathway between the limbic forebrain and tegmental motor systems. It does not correspond to those parts of the lateral hypothalamus thought to control normal feeding.     

Eating or drinking elicited by direct adrenergic or cholinergic stimulation of hypothalamus

A double cannula system, allowing repeated stimulation of central structures with crystalline chemicals, was developed. This technique was employed to study the effects of adrenergic and cholinergic stimulation of the lateral hypothalamus of rats. Drug-specific effects on the feeding and drinking mechanisms, respectively, were observed.     

Parasympathetic ganglia: activation of an adrenergic inhibitory mechanism by cholinomimetic agents

Electrical stimulation of the sympathetic nerves to the urinary bladder or the intraarterial administration of the cholinomimetic substances acetylcholine or methacholine produced adrenergic inhibition in parasympathetic ganglia on the surface of the bladder. The inhibition appeared to be mediated, at least in part, via adrenergic inhibitory neurons located in the pelvic plexus. Atropine blocked the inhibitory response to injected cholinomimetic agents but did not alter the response to stimulation of the sympathetic nerves. Thus, the inhibitory neurons can be activated via both muscarinic and nonmuscarinic receptors, the latter being of primary physiological importance.     

Ontogeny of gastric acid secretion in the rat: evidence for multiple response systems

Gastric acid secretion has been thought to depend on histamine stimulation of the parietal cell. However, in the 2-week-old rat neither exogenous histamine nor the H-2 receptor agonist impromidine stimulates acid secretion, whereas pentagastrin and the cholinergic agent bethanechol are potent stimuli. At this age, the effect of pentagastrin in acid secretion is not blocked by the H-2 receptor antagonist cimetidine, nor is it potentiated by impromidine. These data suggest that, in the rat pup, the acid secretory response to pentagastrin and cholinergic agents occurs before the histamine-mediated system is functional and operates independently of the actions of histamine.     

Centrifugal arousal in the olfactory bulb

The electrical activity of the olfactory bulb was recorded in awake, unrestrained cats with electrodes permanently implanted. It was found that any kind of sensory stimulation producing alertness or arousal brought about the appearance of bursts of rhythmic activity, the magnitude of which was related to the degree of alertness of the cat.     

木霉对玉米叶斑病菌拮抗机制研究

用7种木霉分别对突脐蠕孢菌(Exserohilum turcicum)、新月弯孢霉(Curvularia lunata)进行对峙培养,研究二者的拮抗机制。结果表明,在室内哈茨木霉和顶孢木霉对玉米大斑病菌有较强的拮抗作用,但7种木霉对新月弯孢菌抑制作用不是很强。     

Ontogeny and peripheralization of thymic lymphocytes

Reciprocal transplantation of undifferentiated thymic primordia between diploid and triploid chromosomally marked frog embryos has revealed that thymic lymphocytes are ontogenically derived from elements of the thymic primordium rather than from blood-borne stem cells that migrated into the developing organ. Virtually all the lymphocytes in the spleen, kidneys, and bone marrow of adult frogs are descendants of these original thymic stem lymphocytes.     

EST同工酶在家鸡个体发生中的表达特征

通过对家鸡胚胎期１～１６日龄全胚以及不同生长阶段肝、心、肾、眼、脑、胸肌各组织的ＥＳＴ同工酶ＰＡＧＥ分析表明，酶谱既呈阶段性表达，又具组织器官特异性表达，且谱带多少与活性和该组织器官执行的生理功能相吻合。在某些组织ＥＳＴ同工酶呈现较高程度的多态性。此外，对ＥＳＴ同工酶的遗传基础及其在个体发生中差别表达的调节进行了讨论。     

Unexpected adrenergic effects of chlorpromazine: eating elicited by injection into rat hypothalamus

Although chlorpromazine is believed to block adrenergic transmission, injection of this drug into the hypothalamus of satiated rats does not block norepinephrine-elicited eating, but instead mimics norepinephrine by eliciting eating. The amount of eating elicited by norepinephrine and by chlorpromazine is reliably correlated. These results suggest that endogenous norepinephrine mediates eating elicited by centrally injected chlorpromazine.     

Prolactin and growth hormone release by morphine in the rat: different receptor mechanisms

Concentrations of prolactin and growth hormone in the serum of rats were significantly increased by morphine. Dose response studies demonstrated that maximum prolactin release required lower doses of morphine than those needed for the maximum growth hormone response. Selective blockade of mu 1 (high affinity) opiate receptor with the irreversible antagonist naloxazone reduced morphine-induced peak concentrations of prolactin by 80 percent while increasing peak growth hormone levels by 250 percent. These results suggest different receptor mechanisms for the opiate modulation of the two hormones. The mu 1 (high affinity) receptor sites appear to mediate the morphine-induced release of prolactin but not growth hormone.     

Light adaptation in the rat retina: evidence for two receptor mechanisms

Light adapting the rat retina with transient white flashes too dim to bleach a substantial amount of visual pigment produces a change in electroretinogram spectral sensitivity and an increase in flicker fusion frequency. Increment threshold curves obtained with a long wavelength adapting stimulus and a short wavelength test stimulus show rod saturation.     

多胺在高等植物个体发育中的作用

多胺作为具有调控作用的生理活性物质,与高等植物生长发育关系密切。大多数研究表明,多胺在一定的浓度范围内对种子萌发、植物生长与分化有促进作用。在植物花芽分化过程中,多胺水平会发生显著的变化,单独或混合外施Spm、Spd与Put能够促进花芽形成,增加花芽的数目。多胺对植物雌雄蕊、果实的发育与坐果具有重要调节作用,雌花与雄花所包含的多胺在种类及数量上均有差异。而多胺延缓衰老的作用在植物中普遍存在。因此,多胺参与了高等植物个体发育的各个环节。     

Excitatory and inhibitory effects of opiates in the rat vas deferens: a dual mechanism of opiate action

Both natural (-)-morphine and its unnatural enantiomer (+)-morphine exert an excitatory action on electrically stimulated contractions of rat vas deferens. Preexposure to (-)-morphine results in cross-tolerance to the inhibitory action of beta-endorphin. (-)-Naloxone and its stereoisomer (+)-naloxone also exert an excitatory action, but only (-)-naloxone bocks the inhibtory action of beta-endorphin. Thus morphine exerts a dual action on a peripheral organ: one an inhibitory action mediated by the stereospecific endorphin receptor that is blocked stereospecifically by naloxone, the other an excitatory action mediated by a nonstereospecific receptor that is not blocked by naloxone. The opiate abstinence syndrome is seen as due to the unmasking of the excitatory action of opiates when its concomitant inhibitory influence is removed by selective blockade by naloxone or weakened by selective tolerance. The view that the rat vas deferens is devoid of morphine receptors is now seen as arising from a reverse example of morphine's dual action: the masking of the inhibitory action of morphine by its concomitant and more potent excitatory action.     

猪脾生长抑素阳性细胞和免疫细胞的发育

用免疫组织化学技术研究猪脾生长发育过程中生长抑素 (SS)阳性细胞、IgA阳性细胞和酸性非特异性脂酶(ANAE)阳性细胞数量的变化。结果表明 ,出生时 ,猪脾SS阳性细胞数量较少 ,3日龄时数量显著增加 (P <0 0 5 ) ,2 0日龄则极显著增加 (P <0 0 1) ,并维持到 90日龄 ,12 0日龄时SS阳性细胞数量显著减少 (P <0 0 5 )。出生时 ,猪脾内就分布有IgA阳性细胞和ANAE阳性细胞 ,IgA阳性细胞数量于 2 0日龄呈显著上升趋势 ,4 5日龄达最高峰 ,于 90日龄极显著降低 (P <0 0 1) ;ANAE阳性细胞数量在 2 0日龄开始增加 ,4 5日龄时极显著增加 (P <0 0 1) ,12 0日龄时又显著降低 (P <0 0 5 )。以上结果表明 ,猪脾中SS阳性细胞的发育对免疫细胞的发育具有重要的调节作用     

Adenosine 3',5'-monophosphate content in rat caudate nucleus: demonstration of dopaminergic and adrenergic receptors

Dopamine, apomorphine, isoproterenol, and norepinephrine each increased the concentration of adenosine 3',5'-monophosphate in slice of rat caudate nucleus. The concentrations of dopamine, apomorphine isoproterenol, and norepinephrine causing half-maximal increases were 60, 150, 0.03 and 30 micromoles per liter, respectively. The effect of dopamine was blocked by fluphenazine, a dopamine receptor antagonist, but not by propranolol, a beta-andrenergic receptor antagonist. Conversely, the effect of isoproterenol was blocked by propranolol but not by fluphenazine. The results suggest that in rat caudate nucleus there are two distinct catecholamine receptors capable of causing increased concentrations of adenosine 3',5'-monophosphate, one having the characteristic of dopamine receptor, and the other having the characteristics of beta-adrenergic receptor.     

鸡胚胎腺垂体促甲状腺激素细胞的发生及其变化

应用免疫组织化学方法,对第3.5～20.5 d鸡胚腺垂体促甲状腺激素亚单位(TSH撸┫赴姆⑸⑹亢托翁植急浠媛山辛搜芯俊=峁允荆杭ε叻⒂牡?0.5 d,有少量TSH呦赴植加谙俅固迩耙叮赴派常伲舜螅患ε叻⒂牡?4.5 d以后,TSH呦赴灾黾樱≒ < 0.05),细胞体积增大,胞浆增多,细胞着色浓,分布于腺垂体前叶边缘区,少量分布于后叶背侧。研究结果证明,鸡胚腺垂体TSH呦赴⑸谂咛シ⒂闹衅冢幌赴脑鲋撤只谭⑸诩ε叻⒂闹泻笃冢籘SH的合成和分泌功能在胚胎发育的后期最旺盛。TSH呦赴植加谙俅固迩耙逗秃笠侗巢唷?