UMLS:C0344307 - FACTA Search

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Query: UMLS:C0344307 (analgesia)
28,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anti-writhing assays to detect analgesia or specific activity against selected agonists were performed on albino mice. Acetylcholine Cl, bradykinin triacetate, phenylquinone, and serotonin creatinine sulfate were used as agonists. 10 compounds, including 5 standard analgetics, were tested against each agonist. Attempts to study histamine phosphate as an agonist were not successful. Results of these investigations showed satisfactory analgetic acitivity for codeine phosphate and acteyl salicylic acid (ASA) in all assays. weaker analgetics displayed varying degrees of activity depending on the agonist tested. Acute oral toxicities were determined for the 10 test compounds and the analgetic ED50 vs the LD50 of each compound was compared. The data confirmed the nonspecificity for writhing assays as well as a variability in activity of the test compounds against the various agonist.
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PMID:Comparative analgetic testing of various compounds in mice using writhing techniques. 58 70

.1 mol/L CaCl2 0.5 microliters, 0.06 mol/L ACh 0.5 microliters, 5.4 x 10(-3) mol/L gallamine triethiodide (cholinergic nicotinic receptor blocker) 0.5 microliter and 14.4 x 10(-3) mol/L atropine (cholinergic muscarinic receptor blocker) 0.5 microliter were injected through bilateral intracranial cannulae in rat habenula. Pain threshold was measured by the latency of tail-flick reflex elicited by radiant heat exposure before and after intracerebral injection. CaCl2 significantly reduced the basic pain threshold and weakened the effect of the acupuncture analgesia. ACh apparently antagonized the effect of acupuncture analgesia. Gallamine triethiodide could recover the pain threshold almost to the raised level by acupuncture, but atropine only strengthened the effect on pain threshold weakly and briefly. The results suggest that the antagonistic effect of Ca2+ may be mediated via ACh in habenula.
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PMID:[Antagonistic effect of electro-acupuncture analgesia with Ca2+ injection into habenula could be reversed by gallamine triethiodide]. 129 45

The article systematically reported our physiological and biochemical work on the relationship between central acetylcholine and acupuncture analgesia. The results indicate: 1. Acupuncture on acupoints could produce analgesia. 2. Ach contents in cerebrospinal fluids and brain increased under acupuncture analgesia. 3. AChE activities iu brain elevated under acupuncture analgesia. 4. ChE inhibitor reinforced the effects of acupuncture and inhibitor of ACh synthesis could inhibit the effects of acupuncture, which could be reversed by administration of ACh and chlorocholine. M-AChR antagonists could also inhibit the effects of acupuncture. 5. The turnover rate of ACh in diencephalon, caudate nucleus and spinal dorsal horn accelerated when acupuncture analgesia. The discussion was given on the variation of metabolic dynamics in combination with related literature.
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PMID:[Research on the relationship between central acetylcholine and acupuncture analgesia]. 191 33

In this paper a preliminary study was made about the relationship between ACh and the primary input of acupuncture sensation based on the changes of content of ACh, its synthetic enzyme (choline acetylase, or ChAC) and its degradation enzyme (acetylcholinesterase, or AChE) in the dorsal horn of the spinal cord and spinal ganglia. The results were found that: 1) EA at "huantiao" exerted a marked analgesia effect, the acupuncture analgesia was inhibited when the lateral dorsal root was cut off. 2) The content of ACh of the EA group were slightly lower than those of the control group. 3) AChE activity in the spinal ganglia and the dorsal horn increased markedly under electroacupuncture stimulation. 4) The activity of ChAC in the dorsal horn of rats under acupuncture stimulation was significantly higher than those of the control group. 5) ACh content in the spinal ganglia increased obviously when the degradation of peripheral ACh was inhibited by prostigmine. 6) With the lumber dorsal roots excised, AChE activity of the operative side were much lower than those of the intact side during EA stimulation. It suggest that the metabolism of ACh in the dorsal horn of the spinal cord and spinal ganglia change during the course of EAA, and only when signals produced at the acupoints are delivered to the spinal cord via ACh-containing primary somatosensory nerves, can they exert analgesic and therapeutic effect of acupuncture.
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PMID:[The change of ACh metabolism in the dorsal horn of spinal cord and spinal ganglia during electroacupuncture analgesia (EAA)]. 211

In order to investigate the correlation between the peripheral ACh and the primary input of acupuncture sensation, in the paper the cholinesterase inhibitor--Neostigmine and the ACh synthesis blocker--Hemicholine, which are unable to pass through blood brain barrier, and ACh were used as tools to increase or decrease the level of ACh in peripheral nerve system of rats. The results indicated that: 1) The effect of electroacupuncture analgesia can be enhanced by subcutaneous injection of neostigmine which related to the dosage used. 2) The influence of electroacupuncture analgesia can be markedly inhibited by intraperitoneal injection of Hemicholine. 3) This influence of suppression by Hemicholine can be reversed at once when acetylcholine in combination with neostigmine was injected. But could not reverse by neostigmine alone. It suggested that the effect of electroacupuncture analgesia and the primary input of acupuncture sensation were significantly related to the level and content of ACh in periphery.
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PMID:[Acetylcholine and the primary input of acupuncture sensation--influence of peripheral acetylcholine on the role of electroacupuncture analgesia]. 212 63

Suppression of behavior accompanying increased ACh synthesis in the brain might account, at least in part, for the preferred use of lithium in antimanic therapy. Three experiments using rats as subjects were designed to test hypotheses about relationships among lithium, ACh synthesis and behavior. Experiment 1 established that hyporeactivity and greater exploratory behavior occurred in animals under LiCl treatment conditions shown to stimulate cholinergic activity in brain. Experiment 2 provided evidence of significant differences between controls and animals on the LiCl diet. Groups tested after 1 or 2 days of LiCl showed the decrease in reactivity to successive presentations of a loud auditory stimulus which characterizes the normal process of habituation. Groups tested after 5 or 10 days of liCl showed no evidence of habituation, their reactivity throughout the period of stimulation being at a level attained by the other groups when habituation reached its final asymptote. Experiment 3 established that effects of LiCl treatment were not manifested in all aspects of behavior: there was no evidence of impairment of motor activity or coordination; no analgesia; no impairment in sensory input nor in acquisition of new behaviors. The effect of the LiCl treatment was not complete inhibition but instead suppression of reactivity to environmental stimulation under conditions shown previously to increase cholinergic activity in brain.
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PMID:Effects of lithium on behavioral reactivity: relation to increases in brain cholinergic activity. 678 2

Acetylcholine (ACh) and norepinephrine (NE) have been identified previously as putative nociceptive neurotransmitters in the mesencephalic reticular formation (MRF) of the rat because they frequently mimic the change in neuronal firing (usually an increase) evoked by a noxious stimulus (NS). The purpose of this study was to determine if 1.) morphine (M) acts to prevent the increase in firing evoked by a NS by blocking the effects of either of these two neurotransmitters and 2.) if this effect is a specific narcotic effect. Using the technique of microiontophoresis in conjunction with extracellular recording, we located single units in the MRF in which 1.) neuronal firing was accelerated by a NS: 2.) M blocked this response; and 3.) either ACh or NE mimicked the effect of the NS. Neurons meeting these three criteria were studied further to determine if morphine would also block the response to either of the neurotransmitters and if this was a specific narcotic effect. We found that morphine blocked the increase in neuronal firing evoked by the NS and ACh or the NS and NE in over 50% of the cells meeting the above criteria. Some neurons were found in which both ACh and NE mimicked the NS and M blocked all three responses. This blockade of these neurotransmitters was a specific narcotic effect because it could be reversed by the systemic administration of naloxone. These data lead to the tentative hypothesis that M, acting via an opiate receptor, blocks the increase in neuronal firing evoked by a NS by blocking the postsynaptic effects of either ACh or NE. This may be one of the mechanisms by which morphine acts to produce analgesia.
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PMID:Interactions of morphine with putative neurotransmitters in the mesencephalic reticular formation. 682 9

The present work is an attempt to elucidate: (1) whether highly rigid structural analogs of acetylcholine are still capable of activating the muscarinic receptor; (2) whether such analogs, be they agonists or antagonists, discriminate among the various ACh-mediated functions, thereby providing a tool for the study of a possible receptor heterogeneity; (3) whether structural rigidity is a significant factor in the kinetics of drug-receptor interaction. To this end, we investigated some properties of drugs in the spiro-(1,3-dioxolane-4,3')-quinuclidine system (SDQ) which embodies the muscarinic pharmacophore in a framework of utmost rigidity. Wherever possible, these properties were compared with those of a closely related but more flexible analog. Variation in effect between members of a rigid-flexible pair or among drugs of varying rigidity is considered to reflect varying affinities towards various sites of action. 2-Methyl-spiro-(1,3-dioxolane-4,3')-quinuclidine (AF-30) is a weak but selective muscarinic agonist. It can be viewed as a highly rigid version of 3-acetoxyquinuclidine (3-AcQ) and it can be used as a probe for detection of heterogeneity among muscarinic receptors. AF-30 is equipotent with 3-AcQ in causing tremors (mice), but has 1/17th the activity of 3-AcQ in the guinea-pig ileum, 1/30th in lowering blood pressure (cats) and 1/10th in inducing analgesia (mice). 2-Diphenylmethyl-spiro(1,3-dioxolane-4',3)-quinuclidine (AF-41) and 2.2-diphenyl-spiro-(1,3-dioxolane-4,3')-quinuclidine (AF-32 are potent antagonists and possess KD values in the same range as those of the more flexible congener 3-diphenylacetoxy-quinuclidine (AF-43) and atropine (0.6--2 nM) but with koff = 0.1 msec-1 (AF-41) and koff = 1 msec-1 (AF-43) (carp atrium). Thus, duration of drug action of drug action at the receptor is a function of structural rigidity in the drug molecule, termination of action being fastest with the flexible molecules. Differences in rigidity among various antagonists also find expression in an unequal distribution of potencies in various tests; thus the rigid antagonists differentiate between two central effects in mice, viz., prevention of oxotremorine-induced tremors and fall from the rotating rod by a factor of 1:20 (especially AF-41 versus AF-43), whereas the more flexible antagonists (AF-43, atropine or even 3-quinuclidinyl-benzilate) do not show such as a selectivity. The existence of heterogenous muscarinic receptors can be inferred from data presented. Both theoretical and practical implications are discussed.
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PMID:Does rigidity in structure of muscarinic agonists and antagonists reflect drug specificity? 723 38

This study aimed to investigate the role of ACh in SmI emanating descending modulation of thalamic Pf neurons in acupuncture analgesia. Multi-micropipettes were used for both extracellularly recording responses of thalamic Pf neurons to noxious stimulation of the plantar area and drug application in rats. It was found that (1) lesion of SmI obviously attenuated the inhibitory effect of EA applied at "Zusanli" and "Huantiao" points on nociceptive responses in Pfneurons; (2) after lesion of SmI iontophoretic application of ACh markedly suppressed the nociceptive responses of Pf neurons, which was significantly different from the effect of iontophoretic NaCl (as the control) showing no influence on them; (3) the inhibition induced by iontophoretic ACh applied in the rats with lesion of SmI was similar to that produced by EA applied in those with SmI intact. It is indicated that EA can activate SmI to release ACh to exert descending modulation, in which ACh is involved in SmI originating descending regulation of Pf neruons in acupuncture analgesia.
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PMID:[Influence of SmI lesion on acupuncture-induced analgesia in thalamic Pf neurons and effects of iontophoretic ACh on their nociceptive responses]. 764 94

(-)-Nicotine, the prototypical agonist for neuronal nicotinic acetylcholine receptors (nAChR) has been shown to bind with high affinity to the rodent and avian alpha 4 beta 2 nAChR subtype. This subtype may represent a primary molecular target for some of the beneficial central nervous system effects i.e., cognitive enhancement, anxiolysis, analgesia, neuroprotection, of (-)-nicotine and related ligands. However, a detailed study of the human alpha 4 beta 2 subunit combination has not yet been reported. In this study, we stably coexpressed the human neuronal alpha 4 and beta 2 nAChR subunits in human embryonic kidney (HEK) 293 cells and studied its pharmacological and regulatory properties. [3H]Cytisine bound to stably transfected cells with high affinity (KD value, 0.2 +/- 0.04 nM) and with a Bmax value of 1359 +/- 91 fmol/mg protein. A good correlation (r = 0.98) was observed between binding affinities in transfected cells and in native neuronal preparations for a series of nAChR ligands. 86Rb+ efflux studies showed that stably transfected cells express functional ion channels that are sensitive to blockade by dihydro-beta-erythroidine. (+/-)-Epibatidine, (-)-nicotine, 1,1-dimethyl-4-phenylpiperazinium, (S)-3-methyl-5-(1-methyl-2-pyrrolidinyl)isoxazole (ABT-418), acetylcholine and (-)-cytisine stimulated 86Rb+ efflux with EC50 values of 0.02, 3.9, 2.5, 10, 44 and 38 microM, respectively. Treatment of transfected cells with (-)-nicotine for 7 days led to a significant increase in the density of [3H](-)-cytisine binding sites (EC50 = 0.56 microM) and a significant enhancement in the sensitivity of ACh. Specific binding or (-)-nicotine-evoked cation efflux was not detected in untransfected cells. Analysis of total cellular RNA from transfected, but not untransfected cells, showed the expected fragment sizes corresponding to the human alpha 4 and beta 2 subunit mRNA. These results demonstrate that stable expression of the human alpha 4 beta 2 nAChR subunit combination can give rise to functional ion channels that bind [3H](-)-cytisine with high affinity, exhibit homologous regulation and evoke agonist-induced cation flux with pharmacological properties consistent with native neuronal alpha 4 beta 2 nAChR.
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PMID:Stable expression, pharmacologic properties and regulation of the human neuronal nicotinic acetylcholine alpha 4 beta 2 receptor. 855 45

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