Superior Cervical Ganglion Of Cat Research Articles

Physical state of tyrosine hydroxylase in the ganglia and nerve endings

1. The distribution of tyrosine hydroxylase was studied in the cat superior cervical ganglia and in the nictitating membrane. The enzyme was present in a soluble and in a particulate form. 2. While in the cell bodies 76% of the total enzyme activity was found in the soluble fraction, in the nerve endings there was almost an equal proportion of both forms. 3. The K m for the substrate tyrosine was similar for both forms, but the K m for the cofactor, reduced pteridine, was 3 times lower for the particulate form than for the soluble form. 4. The concentration of dopamine required for 50% inhibition of tyrosine hydroxylase was similar for soluble and particulate forms of enzyme. 5. Heparin increased markedly the activity of the soluble form of the enzyme and had only a slight effect on the particulate enzyme. 6. Nerve stimulation at 5 or 10 Hz for 30 min did not result in a modification of proportions of soluble and particulate tyrosine hydroxylase, in spite of the fact that hydroxylation of tyrosine was increased under these conditions. 7. Phenoxybenzamine or reserpine did not increase the proportion of the particulate form.

Electron microscope localization of acetylcholinesterase and butyrylcholinesterase in the superior cervical ganglion of the cat. I. Normal ganglion.

The distributions of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in the superior cervical ganglion (SCG) of the cat were determined by electron microscopy (EM) with the bis-(thioacetoxy)aurate (I), or Au(TA)2, method. Before the infusion of fixative, one of the enzymes was selectively, irreversibly inactivated in vivo, as confirmed by light microscope (LM) examination of sections of the stellate ganglion stained by the more specific copper thiocholine method. Physostigmine-treated controls, for inhibition of AChE or BuChE, were stained concomitantly with tissue for enzyme localization by the Au(TA)2 method for EM examination in each experiment. It was concluded that most of the AChE of the cat SCG is present in the plasma membranes of the preganglionic axons and their terminals, and in the dendritic and perikaryonal plasma membranes of the postsynaptic ganglion cells. BuChE is confined largely to the postsynaptic neuronal plasma membranes. Reasons for the discrepancies between the localizations found by the present direct EM observations and those deduced earlier from LM comparisons of normal and denervated SCG are discussed. It is proposed that a trophic factor released by the preganglionic terminals is probably required for the synthesis of postsynaptic neuronal AChE, and that BuChE may serve as a precursor of AChE at that site.

Effects of temperature on coated vesicle formation within pre-synaptic terminals in cat sympathetic ganglia stimulated in vitro

Many workers have shown the depletion of synaptic vesicles following nerve stimulation but there is a discrepancy among data regarding the appearance of coated vesicles attendant on the decrease in the number of synaptic vesicles (Heuser and Reese, 1973; Ceccarelli et al., 1973; Pysh and Wiley, 1974). The present experiment was an attempt to investigate the effect of temperature on stimulation dependent coated vesicle formation.Dissected cat superior cervical ganglia were incubated in Krebs solution at 10°C and 37°C respectively. Preganglionic nerves were stimulated with the electrical parameters consisting of 1 msec square pulses of 20 V at 10 Hz for 30 min. After stimulation the ganglia were fixed with 2 % 0s04 (lh). To examine the participation of the coated endocytosis on recovery processes some ganglia were stimulated at 37°C for 30 min and then rested either at 37°C or 10°C for 5 and 15 min before fixation. The fixed material were then processed for electron microscopy with conventional method consisting of uranyl acetate block stain (30 min), dehydration with ethanol series, and embedding in Epon 812.

Toxicology of helium diving environments: Protective effects of raised he pressure on cholinergic activation in ganglia

The effect of helium gas in He O 2 breathing gas mixtures on excitability of the cholinergic component of ganglionic transmission has been studied in the cat superior cervical ganglion preparation (SCG) under hyperbaric conditions. The depression of SCG sensitivity to acetylcholine (ACh +) stimulation seen at 0.80 atm pressure of He (in 1 atm He O 2 , relative to 1 atm N 2 O 2 ) is fully reversed when the partial pressure of He is raised to 14.4 atm. Additionally, high pressure He stabilizes the amplitude of ACh +-stimulated SCG response over a 2-hr interval, reversing the temporal decay pattern seen in 1-atm experiments with He O 2 or N 2 O 2 .

158) - Involvement of coated endocytic processes in recovery mechanisms for depolarization-induced Presynaptlc morphological changes in isolated cat superior cervical sympathetic ganglia

158) - Involvement of coated endocytic processes in recovery mechanisms for depolarization-induced Presynaptlc morphological changes in isolated cat superior cervical sympathetic ganglia

A long‐lasting potentiation of transmitter release related to an increase in transmitter stores in a sympathetic ganglion

1. High frequency preganglionic nerve stimulation increases the acetylcholine (ACh) stores of the cat superior cervical ganglion. The increase reaches a maximum 20 min following 60 min conditioning stimulation at 20/s. The effect of this conditioning on ACh release in ganglia perfused with plasma and test stimulated at 4 or 5/s has been studied, and the relationship of ACh stores to ACh release in conditioned ganglia determined.2. The rate of ACh release in response to test stimulation at 5/s for 15 min, starting 20 min following conditioning, was 174% of the rate found in unconditioned ganglia. The ACh stores of the conditioned ganglia at the end of the test were calculated to be 173% of the control ganglion stores.3. When test stimulation at 4/s was started 5 min following conditioning, the rate of ACh release showed a variable pattern of increase and decrease over a 75 min period. The mean peak rate of release was about 150% of the control rate, and the duration of potentiation was about 75 min.4. When conditioned, unperfused ganglia were tested by stimulation at 4/s the ACh stores were found to increase and decrease in parallel with the increase and decrease in ACh release rates found in the perfusion experiments.5. It was found also that the magnitude of the increase in ACh stores and ACh release was related to the amount of ACh in the ganglionic stores at the onset of conditioning, being greater for the ganglia with the smaller initial stores.6. It is concluded that the potentiation of ACh release in ganglia conditioned in this way is directly related to the accompanying increase in ACh stores.7. The possible significance of alterations of ACh stores and ACh release as a mechanism of modulatory control of ganglionic transmission is discussed.

Prevention by drugs of tachyphylaxis at nicotinic receptors in the cat superior cervical ganglion in situ

A new copound, AF3 (4-ethyl-6-oxa-1-azatricyclo(4.2.2.0 2,7)dodecan-5-one), and its 4-phenyl analogue, AF6, embodying the structural elements of acetylcholine in a highly rigid rframework, were shown to evoke nicotine-like responses in the nictitating membrane (NM) and blood pressure when applied to the superior cervical ganglion in anaesthetized cats. In this respect, their equiactive molar ration was (nicotine : 1), 20–30. However, at doses that were too low to evoke any response, AF3 appeared to potentiate the responses to nicotine or tetramethylammonium (TMA) by preventing or abolishing tachyphylaxis to the two latter drugs, the effect being dose-dependent with AF3. DMPP which produces much less tachyphylaxis, or preganglionic nerve stimulation, was little or not potentiated in presence of AF3. It is proposed that potentiation to nicotine or TMA occurs following occupancy by AF3 of a regulatory subsite, thereby preventing further access to it by nicotine or TMA. In this respect, AF3 plays the role of a “neutral” molecule.

Acetyltriethylcholine: a cholinergic false transmitter in cat superior cervical ganglion and rat cerebral cortex.

Abstract—The accumulation and metabolism of [14C]triethylcholine by cat superior cervical ganglia [rested or stimulated (20 Hz)] and by rat cerebral cortex minces was measured. In ganglia, preganglionic nerve stimulation increased the accumulation (2.4 fold) and the acetylation (5.7 fold) of triethylcholine; however the depletion of the ganglion's acetylcholine content was 9.5 times greater than the amount of acetyltriethylcholine synthesized. In the presence of eserine, neither stimulated nor rested ganglia synthesized any extra (surplus) acetyltriethylcholine. It is concluded that the rate‐limiting step in acetyltriethylcholine synthesis is the acetylation of triethylcholine by choline acetyltransferase. Subsequent preganglionic nerve stimulation of ganglia, which had been stimulated during the exposure to [14C]‐triethylcholine, caused the increased release of only acetyltriethylcholine; the release was frequency‐dependent, required the presence of Ca2+, and was blocked by increasing the ratio of Mg2+/Ca2+ in the perfusion fluid. All of the acetyltriethylcholine which had been accumulated was available for release. Rat cerebral cortex also accumulated triethylcholine and acetylated about 3% of the accumulated choline analogue. Subsequent stimulation by high K+ (46 mM)‐atropine (3 μM) caused the increased release of acetyltriethylcholine from the cortex and this release required the presence of Ca2+. Triethylcholine can therefore form a cholinergic false transmitter in the cat superior cervical ganglion and the rat cerebral cortex.

The uptake, metabolism and release of homocholine: studies with rat brain synaptosomes and cat superior cervical ganglion.

Abstract—The accumulation of [3H]homocholine (3‐trimethylamino‐propan‐1‐01) by isolated synaptosomes prepared from rat brain was resolved kinetically into a high (KT= 3.0 μM) and a low (KT= 14.5 μM) affinity system. Although homocholine was not acetylated by solubilized choline acetyltransferase, 64% of the homocholine accumulated by intact synaptosomes via the high affinity uptake process was acetylated. Homocholine was also acetylated in the superior cervical ganglion of the cat, and the amount of acetylhomocholine formed was increased (12‐fold) by preganglionic nerve stimulation. In ganglia, acetylhomocholine was available for release by preganglionic nerve impulses, and its release was Ca2+‐dependent, It is concluded that homocholine can form a cholinergic false transmitter, and that the substrate specificity of choline acetyltransferase in vitro might be different from that in situ.

Effect of surugatoxin on celiac ganglia in cats (author's transl)

Pharmacological properties of surugatoxin (SGTX), the toxic principle from Japanese ivory mollusc (Babylonia japonica), have been studied. In the present paper, the effect of SGTX on celiac ganglia in cats was investigated by measuring blood pressure from femoral artery and regional blood flow in liver (LBF) and spleen (SBF) of anaesthetized cats. SGTX(50 nmol/kg i.v.) markedly inhibited both the hypertension and changes of LBF and SBF in response to splanchnic (preganglionic) nerve stimulation. On the other hand, it did not inhibit the changes of SBF by splenic(postganglionic) nerve stimulation. The hypertension and changes in LBF and SBF in response to DMPP(94.2 nmol/kg i.v.) were abolished by SGTX(50 nmol/kg i.v.), whereas those to McN-A-343 (94.8 nmol/kg i.v.) were not. SGTX usually enhanced the pressor response to McN-A-343. These results indicate that SGTX has a blocking effect on the nicotinic receptor in celiac ganglia as well as in superior cervical ganglia of cats and rats.

The effect of preganglionic nerve stimulation on the accumulation of certain analogues of choline by a sympathetic ganglion.

1. Cat superior cervical ganglia were perfused with a Krebs solution containing 10(-6) M [3H]homocholine (2-hydroxypropyl-trimethylammonium) or 10(-5) M [14C]triethylcholine (2-hydroxyethyl-triethylammonium). Preganglionic nerve stimulation (20 Hz) increased the accumulation of homocholine (3-2-fold) and of triethylcholine (2-1-fold). This increased accumulation during stimulation was not the result of increased metabolism. 2. The increased accumulation of homocholine or triethylcholine induced by pregnaglionic nerve stimulation was not reduced by tubocurarine or by atropine, but it was blocked by choline and by hemicholinium. These results suggested that preganglionic nerve stimulation increased choline analogue accumulation into cholinergic nerve terminals. 3. The increased accumulation of homocholine or of triethylcholine induced by preganglionic nerve stimulation was reduced when the Ca2+ concentration was reduced and was abolished in the absence of Ca2+. However, changes in the Mg2+ concentration which depressed acetylcholine (ACh) release by amounts comparable to those induced by altered Ca2+ concentrations did not alter the uptake of homocholine or triethylcholine. It is concluded that the uptake of choline analogues is not regulated by transmitter release but that stimulation increases the uptake of the choline analogues by a Ca2+-dependent mechanism. 4. The accumulation of ACh by ganglia perfused with a Krebs solution containing choline and high MgSO4 (18 mM) was measured. The ACh content of these ganglia did not increase, although choline transport presumably exceeded that necessary for ACh synthesis to replace released ACh. It is concluded that choline transport does not limit ACh synthesis in ganglia.

234) - Effects of temperature on the appearance of coated endocytotic vesicles during transmitter release at frog neuromuscular function and cat superior cervical sympathetic ganglion

234) - Effects of temperature on the appearance of coated endocytotic vesicles during transmitter release at frog neuromuscular function and cat superior cervical sympathetic ganglion

Helium depression of cholinergic sensitivity in the cat superior cervical ganglion tissue

The sensitivity of the superior cervical ganglion (SCG) tissue in the cat to activation by infusion of its normal cholinergic agonist acetylcholine (ACh +) has been compared for animal preparations breathing normal air and those breathing helium-oxygen ( 80% 20% ) at 1 atm. The ganglionic response to infusion of a 1.0 × 10 −3 m bolus of ACh + solution delivered intra-arterially to SCG tissue is approximately 15% less in HeO 2 breathing atmospheres than in N 2O 2. The response decay curves with increasing exposure time for the cat preparation in either breathing atmosphere are linear, and yield net decreases of 10–15% of control amplitudes over the course of 2 hr. The observed effect of 0.80 atm of He, relative to N 2, in partial desensitization of cholinergic response at the SCG, is discussed in terms of possible mechanisms of interaction of He with tissue receptor components.

Effect of preganglionic application of vinblastine-impregnated silastic cuffs on acetylcholinesterase, butyrocholinesterase, and acetylcholine contents of cat superior cervical ganglion

Vinblastine sulfate in silastic cuffs was applied to the preganglionic vagosympathetic trunk of the cat superior cervical ganglion in an attempt to assess the role of acetylcholine as a possible neurotrophic factor required for maintaining postsynaptic ganglionic acetylcholinesterase and butyrocholinesterase. Following implantation of 1% (w/w) vinblastine cuffs, specific activities of acetylcholinesterase and butyrocholinesterase in the ganglion decreased to approximately 20 and 50% of control activities, respectively, within 1 week. The acetylcholine content of the superior cervical ganglion of most cats showed a moderate to marked decrease within this period as well. Histochemical findings were indistinguishable from those seen following preganglionic denervation. Because of the similar fall in ganglionic acetylcholine and enzyme contents, results with this technique do not eliminate acetylcholine as a possible neurotrophic factor for the maintenance of postsynaptic ganglionic acetyl- and butyrocholinesterases.

Mechanism of action of Jameson's mamba venom on the superior cervical ganglion of cat

Dendroaspis jamesoni snake venom administered intra-arterially into the superior cervical ganglion, inhibits contraction of the cat nictitating membrane to supramaximal electrical stimulation of preganglionic nerve, when given in large doses, and facilitates it if administered in small doses. The block is at the superior cervical ganglion. The venom did not block the contraction of nictitating membrane to intra-arterial injections of direct depolarizers of the ganglion (1,1-dimethyl-4-phenylpiperazinium, methacholine, potassium chloride) whereas it blocked the contraction of the nictitating membrane to indirect depolarizers of the ganglion (acetylcholine, carbachol) and electrical stimulation of the preganglionic nerve followed by injection of neostigmine intra-arterially during stimulation. Radioactive studies with 45Ca showed that the percentage of injected radioactivity in the first effluent blood sample (1 min) was greater in cats treated with venom (74%) than in control cats (35%). The venom blocks the process, probably involving calcium, concerned in the release of acetylcholine. The venom itself, as judged by chromatographic separation and guinea pig ileal testing, contains acetylcholine or an acetylcholine-like material.

Cholinergic mechanisms in narcotic analgesics

In the last few years, there has been renewed interest in the neurotransmitter acetylcholine (ACh), regarding its involvement in the ascending system of cholinergic neurons, which plays an important role in attention, awareness, and consciousness. Elucidation of the mechanism of action of morphine through cholinergic neurons has been the subject of study of various workers. It was shown that morphine inhibited the release of ACh from electrically stimulated guinea-pig ileum, possibly by an effect on postganglionic elements; also from cat superior cervical ganglion; and from neuromuscular junctions such as rat diaphragm and sartorius muscle. The effect of an antagonist that reverses the depression in ACh release produced by morphine presumably involves removal or displacement of morphine from the tissue sites that it normally occupies; this removal in turn leads to the increase in ACh release. This increased ACh release in the brain may partly be responsible for the hyperactive state that follows the acute withdrawal of morphine in animals. In view of this, it is interesting to note that the use of ACh antagonists has been recommended to ameliorate the abstinence syndrome and chlorpomazine has been used and recommended for the treatment of the narcotic withdrawal syndrome.

The effect of atropine upon acetylcholine release from cat superior cervical ganglia and rat cortical slices: measurement by a radio-enzymic method.

Atropine is known to increase the release of acetylcholine (ACh) from cerebral cortex, and the present experiments tested the effect of this drug upon ACh release in the superior cervical ganglion of the cat. The release of ACh was measured by a radio-enzymic method, which was shown to provide an estimate of the ACh content of samples collected from perfused ganglia that was similar (102%) to that obtained by the method of bioassay more usually used . Atropine (3 X 10(-6) M) increased (3.5 to 4-fold) the amount of ACh released by rat's sliced cerebral cortex incubated in a high (23 mM) potassium medium. However atropine (3 X 10(-6)-3 X 10(-5) M) did not change the amount of ACh released by ganglia during preganglionic nerve stimulation (5-10 Hz). It is concluded that cholinergic nerve terminals in different tissues appear to have different pharmacological properties.

The effect of hemicholinium-3 on choline and acetylcholine levels in a sympathetic ganglion.

Pregangliaaonic stimulation of the cat's superior cervical ganglion in the presence of hemicholinium-3 (HC-3) produced the expected depletion of acetylcholine (ACh) stores, but failed to cause a corresponding reduction in the choline content. These results suggest that either HC-3 possesses an intracellular site of action or that in lower doses it selectively inhibits a specialized choline transport system in cholinergic nerves. At a dose of 2 mg/kg, HC-3 probably blocked ACh synthesis completely in ganglia stimulated at 20 Hz. Under these conditions, there was a rapid depletion of ACh to about 50% of control levels during the first 5 min of stimulation and thereafter the rate of decline in ACh levels proceeded at a much slower pace. Since the 2 mg/kg dose of HC-3 did not raise plasma choline concentrations, it may be assumed that non-specialized choline transport systems in other tissues were not significantly inhibited by this dose of HC-3. However, when the dose of HC-3 was increased to 4 mg/kg, plasma choline levels increased by 58%.

A prolonged after-effect of intense synaptic activity on acetylcholine in a sympathetic ganglion.

The findings was confirmed that there is a "rebound" increase of stored acetylcholine (ACh) in cat superior cervical ganglia conditioned by prolonged preganglionic stimulation at a frequency high enough to cause initial depletion of the store. Ganglia removed immediately after 60 min of continuous or interrupted stimulation at 50 Hz, with chloralose as anesthetic, contained about 30% more ACh than their unconditioned controls; the rebound rose to about 60% after 15 min of rest and then subsided with an apparent half-time of about 2 h. Tests with hemicholinium, combined with hexamethonium or tubocurarine, showed that rebound ACh was located presynaptically and could be released by nerve impulses; but conditioned ganglia perfused with an eserine-containing medium did not release more ACh than their unconditioned controls, except in circumstances in which the mobilization of ACh from a reserve store appeared to be the rate-limiting process for release. The appearance of rebound ACh during and after conditioning stimulation was suppressed by hexamethonium and by tubocurarine, neither of which has much effect on ACh turnover in ganglia excited at lower frequencies, but not only by atropine, noradrenaline, or phenoxybenzamine. The formation of rebound ACH is thus contingent on the postsynaptic nicotinic response to released ACh, and may represent an augmentation of the transmitter store in structures remote from the release sites.

Ganglion blocking activity of amidinothiocholine derivatives.

Some amidinothiocholine derivatives have been prepared and tested for the ganglion blocking activity, as compared with that of hexamethonium. Among them, most potent ganglionic blocking compound was S-(2-trimethylaminoethyl)-1'-ethylisothiuronium which was more potent than hexamethonium on the cat superior cervical ganglion, the guineapig hypogastric nerve-vas deferens preparation and the cat and rat blood pressure. Other compounds, also, had the ganglionic blocking action, but were not so potent as hexamethonium.