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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The possible pathways conducting pain are still being discussed. One of the possible pathways may pass through the centrum medianum (CM). In the present study the activity of neurones of CM in cats was recorded using glass-micropipettes. 3-aminopropansulphonic acid (3-APS), which is a GABA analogue was administered intravenously in a dose of 0.1, 0.2, 0.5 and 1.0 mmol/kg. The depressive effect starts at the dose of 0.2 mmol/kg. The duration of the effect depends on the dose of 3-APS. Hence 3-APS has a very strong effect on other thalamic neurones so that it may be used for influencing their activity.
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PMID:The influence of 3-aminopropansulphonic acid (3-APS) on thalamic neurons. 625 Jan 75

The observation that migraine patients improve during pregnancy with return of headache upon commencement of breast feeding, led Authors to investigate the involvement of Pain Suppressor System (PSS) in pregnancy and after delivery. PSS is a complex system which utilizes neurotransmitters as beta-Endorphine-Like-Immunoreactivity (beta-ELI), 5-Hydroxytryptamine (5-HT), Dopamine (DA) and GABA. The Authors report preliminary results of beta-ELI behaviour in pregnancy and in the immediate post-partum period in rats.
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PMID:[The puerperium and dysnociception. I) Behavior of serum beta-endorphins in pregnant and post-partum animals]. 627 25

THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) is a potent and specific GABA receptor agonist which does not influence the GABA uptake system or GABA metabolizing enzymes. The specificity for the GABA receptor is also demonstrated by lack of action on monoaminergic, cholinergic, histaminergic or opiate receptors. Since in recent years GABA receptor stimulants-among others THIP--have become available many have speculated as to what clinical indication GABA-ergic stimulation might be an important element. The first suggestion was that GABA-ergic drugs by an inhibitory effect on the dopamine neurons would improve the antischizophrenic effect of neuroleptics and improve tardive dyskinesia. Furthermore, studies on brains of deceased Parkinson and Huntington's chorea patients have demonstrated a low level of GABA and its synthesizing enzyme glutamic acid decarboxylase (GAD) in the basal ganglia. Also in epilepsy and diseases with dementia a deficit in the GABA system has been proposed. Therefore a therapeutic strategy for these diseases may be supplementary treatment with drugs which increase GABA receptor activity. Furthermore, recent results in humans have shown that GABA agonists perhaps also could be of benefit in mania and depressions. When considering the neurophysiological elements of nociception and muscle tone it is also reasonable to suggest that GABA-ergic stimulation may reduce pain perception and muscle tone.
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PMID:Pharmacodynamic effects and possible therapeutic uses of THIP, a specific GABA-agonist. 629 18

In decerebrate, cerebellectomized cats, a comparison was made between the effects of electrical stimulation in nucleus raphe magnus (NRM) and iontophoretic application of GABA, glycine, met-enkephalin and beta-endorphin on the responses of neurones in the medial brain stem reticular formation to tooth pulp stimulation. NRM stimulation, GABA, glycine and enkephalin produced a short lasting inhibition of tooth pulp evoked responses whilst the time course of the inhibition produced by beta-endorphin was much slower, often lasting up to 1 h following a 3-7 min ejection period. The effects of GABA and glycine could be antagonised by iontophoresis of bicuculline and strychnine respectively whilst intravenous injection of naloxone antagonised the inhibition induced by the opioid peptides. In most neurones tested, inhibition of tooth pulp evoked responses by NRM stimulation was blocked by iontophoretic application of bicuculline but not by strychnine or naloxone (i.v.). We conclude that GABA may act as a transmitter which mediates the inhibitory effects of NRM on the responses of reticular neurones to tooth pulp stimulation. Thus GABA may be involved in stimulation produced analgesia.
Pain 1983 Feb
PMID:Actions of GABA, glycine, methionine-enkephalin and beta-endorphin compared with electrical stimulation of nucleus raphe magnus on responses evoked by tooth pulp stimulation in the medial reticular formation in the cat. 630 24

THIP, 4, 5, 6, 7-tetrahydroisoxazolo (5,4-) pyridin-3-ol, is a GABA-agonistic drug with analgesic effect, but apparently without respiratory depressant properties in awake subjects. The effect of THIP on the CO2 ventilation response was tested before, during and at the end of halothane anaesthesia in six male patients and compared to a control group. As there was no indication of respiratory depression by THIP, the drug may have a future in the treatment of postoperative pain if an analgesic effect is confirmed under clinical conditions.
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PMID:Respiratory effect of THIP, a GABA-agonistic analgesic, during halothane anaesthesia. 635 58

The analgesic effect of morphine in conditions of serotonin- and GABA-ergic activation was studied in experiments on male albino rats. The serotonin re-uptake blockers fluoxetin and citalopram (10 and 20 mg/kg) did not exert clear analgesic effect or did not potentiate morphine action in doses of 5 and 10 mg/kg. The GABA agonist muscimol (0.5--2 mg/kg) did not influence the pain reaction structure and did not enhance morphine-induced analgesia. The role of serotonin- and GABA-ergic processes in realization of the analgesic action of morphine is discussed.
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PMID:[Possibility of modulating morphine analgesia against a background of activation of serotonin- and GABA-ergic processes]. 697 90

The paper concerns the basic parameters of GABA metabolism in 4 groups of animals: after emotional pain stress; after twofold administration of formalin; after coronary artery ligation; after narrowing of the aorta ostium. GABA metabolism in all brain systems was shown to be activated in all types of exposure to stress. One of the final GABA metabolites, hydroxybutyric acid, prevents undue enhancement of pituitary-adrenal function and injury to the internal organs during stress. This suggests that the GABA-ergic system plays the role of a nonspecific inhibitory mechanism that limits the stress-syndrome and averts stress injuries under exposure of the body to various extreme factors.
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PMID:[Activation of GABA system metabolism in the cerebral hemispheres during exposure to different stress factors]. 719 26

Topically applied norepinephrine, dopamine, serotonin, GABA and glycine, and systemically administered clonidine, L-DOPA (plus carbidopa) and 5-hydroxytryptophan completely suppressed the cutaneous hyper-irritability produced in the trigeminal sensory distribution by picrotoxin overlying the caudal medulla. Cholinergic agents and apomorphine were ineffective. Of the positive compounds, norepinephrine, serotonin and GABA showed the shortest latencies and norepinephrine and serotonin required the lowest concentrations in order to inhibit the hyper-irritability. If L-DOPA (plus carbidopa) was injected after pre-treatment with FLA-63, the effects of L-DOPA did not appear. Similar depression of the hyper-irritability was caused by electrical stimulation of the central gray. The inhibitory effects of stimulation of the central gray was suppressed after administration of tetrabenazine, but again it produced markedly by injection of L-DOPA. From these observations it was concluded that the hyper-irritability could be suppressed by serotonergic as well as noradrenergic fibers terminating at the spinal trigeminal nucleus caudalis. The potential clinical use of L-DOPA in patients with hyperesthesia is discussed.
Pain 1981 Aug
PMID:Inhibitory mechanisms of the hyper-irritability caused by picrotoxin in the rat. 730

Pretreatment (IP) of mice with (-) baclofen, muscimol, 4,5,6,7-tetrahydroisoxazolo (S,4-c) pyridin-3-ol hydrate (THIP), aminooxyacetic acid (AOAA) or gamma-acetylenic GABA caused a dose-dependent inhibition of thelocomotor stimulant effect of phencyclidine (PCP, 8 mg/kg). Although (-) baclofen was found to be the most effective PCP antagonist, its (+) isomer was inactive. The maximum blocking effect of AOAA was seen in animals treated 3 and 6 hr earlier. Except for gamma-acetylenic GABA, none of these drugs significantly blocked the locomotor stimulant effect of d-amphetamine (3 mg/kg, IP). Diazepam reduced d-amphetamine response, but failed to influence PCP-induced stimulation. The locomotor stimulant effect of PCP, unlike that of d-amphetamine, may be the result of a specific GABA antagonistic effect at certain dopamine-rich areas of the brain. It seems that (-) baclofen may prove to be useful in the management of PCP intoxication. Administration of higher doses of PCP (20 and 50 mg/kg) in mice pretreated with (-) baclofen resulted in the development of surgical anesthesia manifested as the loss of a) righting reflex, b) pain sensation and c) corneal reflex. The duration of the general anesthetic response was found to be a function of the doses of both (-) baclofen and PCP. The possible use of (-) baclofen as an adjuvant to general anesthetic is discussed.
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PMID:Interaction between phencyclidine (PCP) and GABA-ergic drugs: clinical implications. 736 54

Transcutaneous electrical nerve stimulation(TENS), acupuncture-needling, and electroacupuncture are useful non-ablative methods in medical practice for relief of pain. These procedures appear to work by causing an increased discharge in afferent nerve fibers which in turn modifies the transmission of impulses in pain pathways. It is known that the mechanism of analagesic effect via these maneuvers are variable depending on the stimulating parameters. For example, the endogenous opioid system is profoundly related to the mechanism when a peripheral nerve stimulation is applied with parameters of low frequency and high intensity. However, when stimulated with parameters of high frequency and high intensity, the reduced activity of dorsal horn neurons is only slightly reversed by a systemic administration of naloxone, a specific opiate antagonist. Thus, the present study was performed to investigate the neurotransmitter that concerns the mechanism of peripheral nerve stimulation with parameters of high frequency and high intensity. We used an iontophoretic application of antagonists of possible related neurotransmitters. The dorsal horn neuron activity which was evoked by squeezing the peripheral cutaneous receptive field, was recorded as an index of pain with a microelectrode at the lumbo-sacral spinal cord. Naloxone, picrotoxin and strychnine were applied at 200nA during a period of conditioning nerve stimulation. We observed the effects of these drugs on the change of dorsal horn neuron activities. The main results of the experiment can be summarized as follows. The spontaneous activity of dorsal horn neurons increased in the presence of glutamate and decreased with GABA. It did not change with naloxone, picrotoxin or strychnine. When naloxone was applied iontophoretically during peripheral nerve stimulation, there was no statistically significant analgesic effect compared with that of the control group. When picrotoxin was applied iontophoretically during peripheral nerve stimulation, the analgesic effect was reduced. When strychnine was applied, the analgesic effect was reduced but did not show a statistically significant difference with the control group. These results suggested that the GABAergic system may have been partially related in the analgesic action of peripheral nerve stimulation with parameters of high frequency and high intensity.
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PMID:Effects of iontophoretically applied naloxone, picrotoxin and strychnine on dorsal horn neuron activities treated with high frequency conditioning stimulation in cats. 748 77


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