m-Octopamine: Normal Occurrence with p-Octopamine in Mammalian Sympathetic Nerves

The development of a radiochemical enzyme assay for p-octopamine in 1969 led to its identification in a large number of invertebrate nerve systems and in mammalian sympathetic nerves. The original method by which p-octopamine was measured has now been found to be nonspecific; however, modifications of this procedure can determine both m- and p-octopamine. We recently developed a new specific method for the unequivocal identification and quantitative determination in tissue of the six octopamine and synephrine isomers. With this method--negative chemical ionization gas chromatography-mass spectrometry--the more physiologically active m-octopamine has been found in association with p-octopamine in 10 organs of the rat. m-Octopamine is present in concentrations equal to those of p-octopamine in heart, spleen, and liver and in concentrations from 30 to 60% of p-octopamine in adrenals, vas deferens, brain, kidney, large intestine, bladder, and lungs. In vivo inhibition of monoamine oxidase markedly increased the concentrations of both m- and p-octopamine in all organs examined. Both amines were virtually absent from all organs except the adrenals following chemical sympathectomy with 6-hydroxydopamine, thereby establishing that m- and p-octopamine are localized within sympathetic nerve endings.     

刺激家兔颈交感神经对颈动脉窦反射的影响

在36只麻醉家兔观察了电刺激颈交感神经(CSN)对颈动脉窦压力感受器(CSB)活动的影响。所得结果如下:(1)电刺激 CSN 可使夹闭颈动脉引起的加压反射消失或倒转,△BP 从刺激前的 39.5±3.6mmHg 变为刺激时的-0.31±5.4mmHg(P<0.001)。(2)在电刺激CSN 时,静注新福林所诱发的颈动脉窦压力感受器-心率反射增强,表现为反射性心率减慢较刺激前更为明显。(3)在以50—200mmHg 的压力充胀两侧颈动脉窦的条件下,刺激 CSN 引起窦内压与平均动脉压的关系曲线下移,与刺激前曲线相比有明显差异(P<0.01)。(4)切断 CSN 后,动脉血压有所升高,提示 CSN 对 CSB 活动有紧张性调节作用。以上结果比较明确地表明家兔 CSN 对 CSB 活动有调节作用。此作用可能是 CSN 作用于窦壁平滑肌而间接引起的。     

Stimulation of DOPA Synthesis in the Superior Cervical Ganglion by Veratridine

We have investigated the effect of veratridine on DOPA (3,4-dihydroxyphenylalanine) accumulation by the superior cervical ganglion of the rat. Incubation of the ganglion with veratridine (50 microM) causes a 10-fold increase in the rate of DOPA accumulation. Veratridine-stimulated DOPA accumulation is blocked by tetrodotoxin, but not by cholinergic or adrenergic antagonists or by decentralization of the ganglion. The cyclic nucleotide 8-bromo cyclic GMP does not increase DOPA accumulation, and 8-bromo cyclic AMP causes only a 2-fold increase in DOPA accumulation, which is additive with the effect of veratridine. Thus, the action of veratridine appears to be independent of these cyclic nucleotides. The effect of veratridine on DOPA accumulation is probably due to a stable modification of tyrosine hydroxylase, since an increase in tyrosine hydroxylase activity can be measured in cell-free extracts of veratridine-treated ganglia. Both the increase in DOPA accumulation and the stable activation of tyrosine hydroxylase are dependent upon extracellular Ca2+. The activation of tyrosine hydroxylase by veratridine may be mediated by the depolarization of, and the subsequent entry of Ca2+ into, ganglionic neurons.     

Location and major postembryonic changes of identified 5-HT-immunoreactive neurones in the terminal ganglion of a cricket (Acheta domesticus)

Summary In the terminal ganglion of the cricket, Acheta domesticus, the somata of certain interneurones and efferent neurones consistently react to 5-HT immunohistochemistry. There are serially homologous pairs of bilateral interneurones seen in the neuromeres of the 7th to the 10th segment and hindgut neurones with their somata located at the posterior median end of the ganglion. In adult crickets, pairs of large efferent neurones with lateral somata supply specific genital muscles in the 8th and the 9th segment of females. In males, only one pair of these efferent neurones supplies genital muscles of the 9th segment only. These identified 5-HT-immunoreactive neurones are not detected in larval crickets before development of the genital apparatus.     

Correlation of neuronal size and peptide immunoreactivity in the guinea-pig trigeminal ganglion

Summary Frequency and size of guinea-pig trigeminal neurones immunoreactive with antisera to -neo-endorphin(-neo-END), dynorphin A-(DYN), vasoactive intestinal polypeptide-(VIP), somatostatin-(SOM), and substance P-(SP) are reported. Co-localisation of the various peptides to the same ganglion cells was investigated immunocytochemically in consecutive 7-m thick paraffin sections. According to their size, all peptide-immunoreactive neurones belong to the class of small ganglion cells. Within this cell group, SP-immunoreactive neurones appear to be the largest, followed by SOM-, VIP-, -neo-END- and DYN-immunoreactive ganglion cells. The observed differences in size are statistically significant with the exception of that between -neo-END and DYN. This finding correlates well with the observed co-occurrence of the two immunoreactive peptides. All -neo-END-immunoreactive perikarya are also reactive to VIP antisera. These neurones are significantly smaller than those containing VIP-immunoreactivity exclusively. Ganglion cells displaying co-existence of -neoEND- and SP-immunoreactivity or VIP- and SP-immunoreactivity are found too infrequently to allow morphometric analysis. Some non-immunoreactive ganglion cells are shown to be approached by dense baskets of VIP-, -neo-END- or SP-immunoreactive varicose fibres, indicating the presence of intraganglionic modulation sites. The combination of immunohistochemistry and morphometry presented in this study allows the differentiation of diverse populations of primary afferent neurones exhibiting peptide immunoreactivity, most likely reflecting their involvement in different central and peripheral reflex arcs and sensory modalities.     

“SIF” cells in the sympathetic ganglia of the bullfrog,Rana catesbeiana: variety in population and innervation

Summary Small intensely fluorescent (SIF) cells appeared singly or, more frequently, in variably-sized clusters in the sacroccygeal 8th and 9th sympathetic ganglia of the bullfrog. Smaller clusters containing only two to nine SIF cells accounted for 61% of 1773 clusters examined. The largest cluster contained 283 cells. The number of cells in individual ganglia also varied from 21 to 3332. SIF cells, solitary as well as in smaller clusters, received no distinct form of the synaptic contact. In contrast, the cells in larger clusters were frequently innervated by nerve endings that were similar in vesicular constitution to the nerve endings on principal ganglion (PG) cells. No synaptic contact was found between SIF cells and PG cells. SIF cells were also characterized by their location in the vicinity of blood capillaries with a continuous endothelium. p]Our observation seems to suggest that larger clusters of SIF cells receiving nerve endings are linked to a paracrine and/or endocrine system. Chemical influence via the blood stream and intraganglionic milieu for non-innervated SIF cells in the solitary or smaller clusters is a subject for speculation. An interneuronal role of SIF cells to relay stimuli to PG cells seems unlikely. The possible functions here assigned to SIF cells could be variable in efficiency depending on their population and density.     

Epinephrine: A Potential Neurotransmitter in Retina

Abstract: Dopamine (DA), norepinephrine (NE), and epinephrine (EPI) are present in rat retina. DA is the major catecholamine, whereas NE and EPI represent ∼5% of the DA content. DA is contained in a subpopulation of amacrine cells and has been the subject of numerous studies. We investigated the origin and properties of NE and EPI in retina. Following superior cervical ganglionectomy, there was a decrease in NE content, but no decrease in EPI or phenylethanolamine- N -methyltransferase (PNMT) activity. PNMT in retina has many of the substrate-specificity and inhibitor-sensitivity characteristics of other tissues. Enzyme activity is enhanced in newborn rats by treatment with dexamethasone. Exposure to a lighted environment increases retinal EPI in normal and superior cervical ganglionectomized rats. EPI content increased for more than 2 h in a lighted environment. We conclude that most of the NE is contained within the sympathetic neurons that innervate the eye from the superior cervical ganglion, whereas EPI is contained in retinal elements that are responsive to photic stimulation.     

Movement of cynomolgus and rhesus monkey spermatozoa collected from the lower female reproductive tract

Postcoital (pc) cervical mucus was collected in 73 menstrual cycles of cynomolgus monkeys and in 43 cycles of rhesus monkeys at 2,6,10,30 hr pc. Videomicrography was used to analyze sperm numbers and movement in the mucus. Both cynomolgus and rhesus monkeys had comparable populations of motile sperm in the mucus at 2 hr pc. However, by 6 hr pc, cervical mucus from cynomolgus monkeys contained twice as many total sperm and motile sperm as mucus from rhesus monkeys (P <.05). Mean swimming speeds of the free-swimming cervical sperm were similar for the two species at this time. No motile sperm were recovered in mucus from rhesus monkeys at 30 hr pc. In cynomolgus monkeys, however, 14 of the 26 animals examined at 30 hr pc had motile sperm in their mucus. These sperm exhibited lower percent molility, percent free-swimming sperm, and swimming speed than those sperm observed at 6 hr pc. Uterine sperm were collected by transcervical or transuterine aspiration from cynomolgus monkeys. In the transcervical technique, sperm were successfully obtained in four of nine animals examined at 6 hr and in four of five animals at 30 hr pc. The percentage of motile sperm in the uterine fluid was high, 82% ± 4%, and the swimming speeds (86 ± 2μm/sec) were higher than those observed in cervical mucus. Approximately 5–10% of the uterine sperm exhibited swimming motions similar to the hyperactivated motility seen in most mammals. These findings indicate that the sperm cervical mucus interaction in vivo in cynomolgus monkeys has more similarities to the human situation than does the interaction in rhesus monkeys.     

Decrease of Atrial Natriuretic Peptide Content in Rat Superior Cervical Sympathetic Ganglion After Denervation and Axotomy

We found atrial natriuretic peptide (ANP), known as a humoral factor in regulating body fluid volume and blood pressure, in considerable quantities in rat superior cervical sympathetic ganglion (SCG) by radioimmunoassay after separation with reverse-phase HPLC. Although the ANP content of the immature rat 1 week after birth was low, it doubled at 2 weeks and then increased gradually, until it reached the adult level. Denervation caused a rapid decrease in the ANP content to half of the intact SCG level after 3 h, which then fell to 10% of the control value on day 2 after operation. The time course of ANP content reduction after denervation was similar but rather faster than that of activity of the acetylcholine-synthesizing enzyme, choline acetyltransferase, an observation suggesting that ANP may partly contribute to cholinergic synaptic transmission. On the other hand, axotomy produced a rather slower decrease in the ANP content than did denervation. Enucleation and sialoadenectomy also caused a considerable reduction of the ANP content. Thus, part of the ANP found in the ganglion is apparently transported from sympathetically innervated extraganglionic organs via retrograde axoplasmic flow.     

Supra-additive stimulation of adenylate cyclase activity by prostaglandin E2 andD-Ala2-met-enkephalinamide in the guinea-pig superior cervical ganglion: Role of Mg2+ ions

Agonists modulation of Mg²⁺-dependent adenylate cyclase activity has been studied in guinea-pig superior cervical ganglion crude membrane preparations. In the absence of receptors ligands, Mg²⁺ stimulates the enzyme in a concentration-dependent manner. The dose-activation curve shows heterogeneity and two components with higher and lower apparent affinity states, are extrapolated. In the presence ofD-Ala²-met-enkephalinamide only one component is present and the apparent affinity of the ganglionic adenylate cyclase system for the divalent cation as well as Vmax are inhibited. On the contrary, prostaglandin E₂ increases affinity and Vmax values of the lower and, to a lesser extent, of the higher Km component. When the two drugs are tested in combination, not only the inhibitory effect of the opiate is overcome, but a large increase of the apparent affinities and Vmax values for both components is obtained, suggesting the involvement of the Mg²⁺-regulated subunits of the adenylate cyclase system in the supra-additive stimulation mechanism of the enzyme.