Enhancement of affinity to receptors in the esterified glucocorticoid, hydrocortisone 17-butyrate 21-propionate (HBP), in the rat liver

To investigate the affinity of glucocorticoid (GC) to its receptor, the binding of [3H]hydrocortisone 17-butyrate 21-propionate ([3H]HBP) and [3H]dexamethasone ([3H]DEX) in rat liver was analyzed kinetically. Scatchard analysis of [3H]hydrocortisone ([3H]HC) binding yielded a curvilinear plot with upward concavity with high and low affinities. The dissociation constant (Kd) value of high affinity was 1.9 nM and of low affinity 68.7 nM. A Scatchard plot of [3H]HBP binding showed a straight line with high affinity. The Kd value was 9.8 nM. The Kd values for the low affinity site of HC were in good agreement with the Ki values obtained from displacement experiments of [3H]DEX and [3H]HBP binding. The Ki values of HC for [3H]DEX and [3H]HBP were 51.9 and 42.3 nM respectively. The association rate constant for HBP to the GC receptor was 2.9 times lower than that for HC. The dissociation rate constant for HBP was 6.1 to 8.3 times lower than that for HC. The Kd values for [3H]HBP (9.5 nM) and [3H]HC (30.0 nM) obtained from the above two rate constants were approximately the same as the Ki and Kd values (in the case of HC, the value of the low affinity site). These results suggest that esterification of the hydroxyl group(s) in the side chain of GC by butyrate and propionate increased the affinity to the GC receptor, and that a decrease in the dissociation rate from the receptor caused the increase in the affinity to the GC receptor.

Body temperature dependency of gastric regional blood flow, acid secretion and ulcer formation in restraint and water-immersion stressed rats

The effect of water temperature during restraint and water-immersion stress (RWIS) on gastric regional blood flow, acid secretion and ulcer formation were compared to those of restraint stress (RS) alone in rats. RS had no effect on the gastric regional blood flow. In contrast, the gastric regional blood flow was significantly decreased by RWIS. A water temperature dependent reduction of gastric regional blood flow induced by RWIS was observed between 20 degrees C and 30 degrees C. The decrease in gastric regional blood flow for RWIS rats was related to a lowering of the body temperature, which almost coincided with the temperature of water for the immersion. The gastric acid output was not influenced by RS. However, RWIS significantly increased the gastric acid output. The temperature of water in order of increasing acid output induced by RWIS was 25 degrees C greater than 30 degrees C greater than 20 degrees C. Little ulcer formation was found in RS rats, while exposure to RWIS caused marked ulceration. The temperature of water in order of severity of ulceration by RWIS was 25 degrees C greater than 20 degrees C greater than 30 degrees C. The severity of ulceration was not related to the decrease in gastric regional blood flow or increase of acid output, but was correlated to the ratio of the gastric blood flow/the acid output. These findings suggest that the decrease of gastric regional blood flow is in good agreement with the fall of body temperature, and the combined effects of the gastric blood flow and the acid secretion are involved in the ulceration caused by RWIS.

Denervation-like postsynaptic supersensitivity to dopamine agonists induced by microinjection of colchicine into the substantia nigra pars compacta

Circling behavior induced by dopamine (DA) agonists following microinjection of colchicine or 6-hydroxydopamine (6-OHDA) into the substantia nigra pars compacta (SNC) or electrolytic lesions of the SNC was investigated. Methamphetamine produced a contralateral circling behavior 3, 7 and 14 days following injection of colchicine into the SNC. Apomorphine produced an ipsilateral circling behavior followed by a contralateral rotation 3 and 7 days after the infusion of colchicine, whereas only an ipsilateral circling behavior was produced by apomorphine on day 14. 6-OHDA lesions of the SNC produced a contralateral circling behavior to apomorphine and an ipsilateral circling to methamphetamine, whereas both apomorphine and methamphetamine induced ipsilateral circling behaviors in rats with electrolytic lesions of the SNC. The possible mechanisms of action of colchicine are discussed in relation to the known effects of colchicine on axoplasmic transport.

Effect of chronic administration of antidepressants on duration of immobility in rats forced to swim

Chronic administration of imipramine and desipramine significantly reduced the duration of immobility in rats forced to swim in comparison with acute administration. However, amitriptyline did not potentiate the reductive effect of chronic administration. Chlorimipramine, a selective serotonin uptake inhibitor, did not affect the duration of immobility in both the acute and chronic administration. On the other hand, the chronic administration of chlorpromazine, haloperidol and diazepam enhanced the duration of immobility, whereas their acute administration had no effect on it. Sulpiride reduced and enhanced the duration of immobility by the acute and chronic administration, respectively. The present results suggest that the chronic administration of drugs to rats in a forced swimming test can clarify the characteristics of the psychotropic drugs.

Behavioral, electroencephalographic and histopathological studies on mongolian gerbils with occluded common carotid arteries

The effect of brain ischemia on passive avoidance test was investigated in mongolian gerbils with ischemia induced by a 5 min bilateral occlusion of the carotid arteries. Severe impairment of memory was apparent when the training session of the passive avoidance test was carried out 2 or 14 days after the bilateral ischemia. Two days after the occlusion, the amplitude of hippocampal theta waves were slightly decreased and Nissl's degradation was apparent in the CA1 neurons in the hippocampus. The changes in hippocampal neurons become progressively more severe. The amplitude of the hippocampal theta waves diminished considerably and the CA1 neurons in the hippocampus disappeared 14 days after the occlusion. We suggest that the hippocampal damage, especially abnormalities in the CA1 neurons, evidenced by histopathological and electroencephalographic results, may be related to deficits in memory following bilateral common carotid arteries occlusion.

Degradation of myocardial structural proteins in myocardial infarcted dogs is reduced by Ep459, a cysteine proteinase inhibitor

The purpose of this study is to clarify whether cysteine proteinases play an important role in the degradation of myocardial proteins in the infarcted tissue. We studied the effects of a cysteine proteinase inhibitor, Ep459, on degradation of cardiac structural proteins caused by ischemia due to coronary artery ligation for 24 h. Proteolytic effects of purified cysteine proteinases on isolated cardiac tissue were also examined. Using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, degradation of cardiac structural proteins, particularly of myosin heavy chain, alpha-actinin and troponin-I was observed in the infarcted tissue. Treatment with Ep459 significantly reduced protein degradation and total activity of cathepsins B and L in the infarcted tissue, compared with the findings in the untreated group. The electrophoretic pattern of the infarcted myocardium was similar to that of myofibrillar proteins degraded by cathepsins B and L. These results suggest that cysteine proteinases, particularly cathepsins B and L, are involved in degradation of myofibrillar proteins in myocardial infarction.

Effects of neuroleptics on hippocampal stimulation-induced 'wet-dog shaking' in rats

The relationship between wet-dog shaking (WDS) and after-discharge (AD), and the effects of neuroleptics on WDS and AD elicited by hippocampal stimulation, were investigated. AD elicited by hippocampal stimulation consisted of primary and secondary phases. The intensity of the WDS during a 150 sec observation period showed two peaks. The intensity of WDS was reached at the 1st and 2nd peak in the 1st and the 2nd phase of AD, respectively. Haloperidol and chlorpromazine significantly and dose-dependently blocked the appearance of WDS. In particular, the number of WDS decreased during the early 1st phase and the 2nd phase of AD, after hippocampal stimulation. When the hippocampus was stimulated at intervals of 24 hr for 3 successive days a week, the number of WDS during 10-40 sec after stimulation decreased gradually and a small peak appeared during 40-60 sec in the 3rd and 4th week group. This pattern is similar to that seen in the chlorpromazine- and haloperidol-injected group. The possibility that seizure susceptibility, when the hippocampus is stimulated repeatedly, mimicks findings in case of blockage of dopaminergic function by the injection of neuroleptics, has to be considered.

[The modes of anti-inflammatory and analgesic actions of 2-[4-(3-methyl-2-butenyl) phenyl] propionic acid (TA-60) and 2-[4-(2,2-dichlorovinyl) phenyl] propionic acid (TA-668) and effect of TA-60 on the gastrointestinal tract]

TA-668 and TA-60, potent anti-inflammatory compounds, showed no inhibition against the dextran-, the serotonin- and the carrageenin + prostaglandin E2 (PGE2)-induced hind paw edemas in rats and neither did typical acidic non-steroidal anti-inflammatory drugs (ANSAIDs) such as indomethacin. On the other hand, salicylic acid, mepirizole and tiaramide X HCl inhibited the hind paw edema induced by carrageenin + PGE2 in rats. TA-668 and TA-60 as well as other ANSAIDs inhibited the arachidonic acid (AA)-induced erythema, but did not inhibit the PGE2-induced erythema. Mepirizole and tiaramide X HCl showed no inhibition against both the AA- and the PGE2-induced erythemas. TA-668 and TA-60 showed analgesic activities in the adjuvant-induced hind paw edematous rats. The analgesic activities of these compounds disappeared when PGE2 was injected into the inflamed paw as well as indomethacin and ibuprofen. It is concluded that anti-inflammatory and analgesic activities of both TA-668 and TA-60 were based on the inhibition of cyclo-oxygenase. TA-60 showed a protective effect against gastric necrosis induced by necrotizing agents such as HCl, NaOH or NaOH + EtOH. TA-60 showed about a 4 times less potent activity than ibuprofen in delay of occurring time of castor oil-induced diarrhea in rats. These results suggest that the slight ulcerating effect of TA-60 on the gastrointestinal tract might be attributed to its gastric protective effect and slight decreasing effect on the gastrointestinal level of PGE2.

Hyperalgesic action in rats of intracerebroventricularly administered arachidonic acid, PG E2 and PG F2 alpha: effects of analgesic drugs on hyperalgesia

Hyperalgesic actions in rats of intracerebroventricularly (i.c.v.) administered arachidonic acid, prostaglandin (PG) E2 and PG F2 alpha were studied. For the analgesic assay, vocalization induced by repetitive electrical stimulation was employed. Administered i.c.v., arachidonic acid (0.1-30 micrograms/rat), PG E2 (0.001-0.3 micrograms/rat) and PG F2 alpha (0.01-3 micrograms/rat) potentiated the vocalization, in a dose-dependent manner. The maximal potentiating doses of arachidonic acid, PG E2 and PG F2 alpha were 10 micrograms/rat, 0.1 microgram/rat and 1 microgram/rat, respectively. Indomethacin and diclofenac produced much more potent analgesic effects in arachidonic acid-induced hyperalgesic rats than in normal rats and in PG E2- and PG F2 alpha-induced hyperalgesic rats, but aminopyrine, acetaminophen and morphine produced the same analgesic effect in both hyperalgesic and normal rats. Linoleic acid, linolenic acid and gamma-linolenic acid also induced a weak hyperalgesia, whereas indomethacin (4 mg/kg) failed to attenuate the vocalization in these unsaturated fatty acids-induced hyperalgesic rats. These findings indicate that the hyperalgesic actions of arachidonic acid and its metabolites are related to mediation or modulation of the central pain pathways, and the pain-relieving properties of acidic nonsteroidal antiinflammatory drugs (NSAIDs) may be, at least in part, involved in central site.

Effects of propranolol on infarct size and the impaired hemodynamics in experimental myocardial infarcted dogs

We studied the effects of propranolol on infarct size and hemodynamic impairment induced by 24 h-coronary ligation. The myocardial infarction produced by the left circumflex coronary artery ligation was more consistent than that induced by the left anterior descending coronary artery ligation, suggesting that the former is a more appropriate experimental model for pharmacological evaluations. Oral treatment with propranolol, 3-30 mg/kg, reduced infarct size and reduced the elevated left ventricular end-diastolic pressure, which was shown to be most closely related with infarct size, in dogs with circumflex coronary artery ligation extending over 24 h. In conclusion, our results indicate that propranolol protects against the enlargement of infarct size and improves the impaired hemodynamics observed in myocardial infarcted dogs with occlusions extending over 24 h, as well as in dogs with less than 24 h-occlusions reported by numerous investigators.

Effect of neuraminidase on diltiazem-mediated alteration of nitrendipine binding in the hog coronary artery

The dissociation constant (Kd) and the maximum number of binding sites (Bmax) of 3H-nitrendipine (3H-NTD) were not altered by neuraminidase (NUase) treatment. The Kd and Bmax values were approximately 0.2 nM and 70 fmoles/mg protein, respectively. The influences of diltiazem on 3H-NTD bindings differed between NUase treated and untreated preparations. Diltiazem increased 3H-NTD (100 pM) binding dose-dependently with a 40% increase at about 10(-6) M in the untreated preparation. After treatment with NUase, a low dose of diltiazem decreased 3H-NTD (100 pM) binding, and the greatest effect was observed at 10(-9) M with a 50% decrease, while at a high dose of diltiazem (10(-6) M), 80% increase of the binding was observed. Scatchard plot analysis indicated that a high dose of diltiazem (10(-6) M) increased only the affinity of 3H-NTD to the binding site in both the NUase-treated and untreated preparations. In the untreated preparation, a low dose of diltiazem (10(-9) M) had no effect on 3H-NTD binding, but in the NUase-treated preparation, diltiazem (10(-9) M) showed opposing effects, namely, an increase and decrease of the binding at low and high concentrations of 3H-NTD, respectively. No straight line was obtained when a hill plot analysis of the effect of diltiazem on 3H-NTD binding was made. These results suggested that diltiazem allosterically regulates dihydropyridine derivative binding, and in this regulation, the concentration ratios between diltiazem and the dihydropyridine derivative is the most important factor. Furthermore, it is suggested that the sialic acid of the proteoglycan is involved in these interactions, especially in the effect of diltiazem on dihydropyridine binding.

Contralateral circling behavior induced by intranigral microinjections of taurine and GABA in rats

Circling behavior induced by unilateral microinjections of taurine and gamma-aminobutyric acid (GABA) into the substantia nigra zona reticulata (SNR) was studied in rats. Both taurine (10-100 micrograms/rat) and GABA (30-300 micrograms/rat) induced the contralateral circling behavior in a dose-dependent manner when they were microinjected into the SNR. Neither compound induced ipsilateral circling. An ipsilateral injection of 6-hydroxydopamine (6-OHDA) into the nucleus caudatus putamen (CPU) caused a reduction of the dopamine (DA) content in the injected side and decreased the circling behavior induced by taurine but not GABA. Electrolesion of the ipsilateral nucleus ventromedialis thalami (VM) decreased both taurine- and GABA-induced circling. In contrast, only GABA-induced circling was reduced by the electrolesion of the ipsilateral nucleus parafascicularis thalami (PF). Electrolesion of the ipsilateral nucleus accumbens (ACB) did not modify the circling behavior induced by GABA, but did decrease the circling induced by taurine. Electrolesion of the ipsilateral globus pallidus (GP) or nucleus entopeduncularis (EP) did not attenuate the circling behavior induced by either taurine or GABA. These results suggest that taurine-induced circling behavior may be mediated by the nigrostriatal-nigrothalamic system, and the ACB. In contrast, the nigrothalamic system may play an important role in GABA-induced circling behavior.

Effects on the caudate spindle in rats of taurine and gamma-aminobutyric acid (GABA) microinjected into the substantia nigra: involvement of the dopaminergic system

Spindle bursts (caudate spindle) were recorded from the frontal cortex in rats. The bilateral intranigral microinjection of taurine suppressed the caudate spindle, whereas the same dose of gamma-aminobutyric acid (GABA) did not suppress the caudate spindle. These results indicate that suppression of the caudate spindle induced by taurine may relate to activation of the nigrostriatal dopaminergic neurons.

Prevention of cerebral vasospasm with OKY-046 an imidazole derivative and a thromboxane synthetase inhibitor. A preliminary co-operative clinical study

The prevention of cerebral vasospasm with OKY-046, an imidazole derivative and a thromboxane synthetase inhibitor, was studied co-operatively at ten neurosurgical services. Intravenous administrations of 2, 5 or 10 mu/kg/minute of OKY-046 were given continuously from the earliest possible day to the 14th SAH-day to 82 patients with ruptured cerebral aneurysm. Sixty-eight patients (83%) showed moderate to high high-density (SAH) in their initial CTs. Angiographic vasospasms were seen in 58 patients, representing 71% of all cases or 81% of the 72 cases for which angiograms were available: the vasospasms of 45 patients (55 or 63%) were moderate to severe. Symptomatic vasospasm occurred, however, only in 27 patients (33%): in 18 of those cases, moreover, the symptoms were mild or transient. The conditions of the patients at one month after the SAH were classified into 9 grades from 0 (normal) to 8 (deceased). Fifty-two patients (63%) were classified as 0 or 1, and 64 (78%) as better than 3 (possible daily life unaided). The administration of OKY-046 was proven to decrease TXB2 in the blood. This paper emphasizes the effectiveness of the drug for symptomatic vasospasm, and supports our previous contention that cerebral microthrombosis may play an important role in the pathogenesis of cerebral vasospasm.

Inhibitory action of taurine on motoneuron of frog spinal cord

Using the sucrose gap method, the effect of taurine on the spinal cord of the bullfrog was investigated. Taurine inhibited the spontaneous potential and the ventral root reflex potential elicited by the stimulation of the dorsal root. The excitability of motoneuron did not necessarily diminish following taurine application. Taurine inhibited the responses induced by excitatory neurotransmitter candidates such as, glutamate and substance P, in a concentration dependent manner in the preparation, where the neurotransmission was abolished by Ca2+-deprivation and/or Mg2+-supplement. From these results, the depressant action of taurine on the electrical activities in the frog spinal cord may be interpreted, in part, by the inhibition of the response evoked by excitatory transmitter at postsynaptic site.

Studies of D-penicillamine on strain variability and lymph node cellularity in adjuvant arthritis

Experiments were performed in order to ascertain the action of D-penicillamine (PA) on adjuvant arthritis (AA) in rats and to develop a quantitative evaluation method for PA-like drugs, using Lewis, SD, and Wistar rats. Rats were inoculated in the tail with 0.6 mg of Mycobacterium butyricum suspended in 0.1 ml of liquid paraffin. PA apparently induced enhancement of arthritis only in Lewis rats with a good reproducibility. The enhancing effect of PA was seen when it was administered during the period from day -7 to day -1, from day 0 to day 6, or from day 14 to day 20. In control group of Lewis and Wistar rats, adjuvant caused a rapid increase in the cell number of lymph nodes just after the inoculation, and also a marked increase in spleen cells coinciding with the development of arthritis. In PA-treated Lewis rats, the cell numbers of lymph nodes and spleen significantly surpassed those of control rats. However, PA induced no difference from control in Wistar rats, which were not sensitive to PA treatment during the course of arthritis. These results indicate that AA in Lewis rats is a good model for evaluating the activities of PA-like drugs and that PA may affect lymphocytes in lymph nodes and spleen and induce severer arthritis in Lewis rats.

Effects on the caudate spindle in rats of dopamine microinjected into the caudate nucleus

We examined the caudate spindle in control and pargyline-pretreated rats following bilateral application of 3 doses (15, 50 and 150 micrograms/site) of dopamine (DA) into the caudate nucleus. The highest dose of DA (150 micrograms) suppressed the spindle, whereas lower doses (15, 50 micrograms) enhanced the spindle in control rats. Haloperidol given into the bilateral caudate nucleus increased the spindle in control rats. In pargyline-pretreated rats, 50 and 150 micrograms DA caused marked suppression, but 15 micrograms DA caused enhancement. These findings indicate that the DA system may mediate the development of the caudate spindle. Suppression of the caudate spindle induced by intracaudate DA injection may be due to stimulation of postsynaptic DA receptors and enhancement mediated by DA autoreceptors on the DA nerve terminals in the caudate nucleus with a subsequent inhibition of DA neurotransmission.

The action of taurine on the response to glutamate in the motoneuron of the isolated frog spinal cord

Using the sucrose gap method, the effect of taurine on the response to glutamate in the ventral root of the isolated frog spinal cord was investigated. The depolarization induced by glutamate was reduced by taurine and the inhibitory action of taurine was antagonized by strychnine, but not by picrotoxin or bicuculline. This action of taurine was also unaffected by tetraethylammonium, 4-aminopyridine and Ringer deficient in sodium ions, but was affected by chloride-free Ringer. Potassium-free Ringer abolished the effect of taurine on the amplitude of the response to glutamate, but not on the rising phase of the depolarization induced by glutamate. Taurine also abolished the after-hyperpolarization induced by glutamate and this was reduced by ouabain or lithium ions. These findings suggest that taurine acts on a glycine receptor to inhibit the response to glutamate, that the action of taurine partly depends on chloride ions, and that taurine inhibits the sodium pump.

Pharmacological studies of furo [3,2-b]indole derivatives. II. Analgesic effect of FI-302, N-(3-piperidinopropyl)-4-methyl-6-trifluoromethyl-furo[3,2-b]ind ole-2-carboxamide, in experimental animals

FI-302, N-(3-piperidinopropyl)-4-methyl-6-trifluoromethyl-furo[3,2-b]indol e-2-carboxamide, is a new non-steroidal anti-inflammatory compound. The analgesic effect of FI-302 was investigated in comparison with those of non-steroidal anti-inflammatory drugs (NSAIDs). In the tail pressure, hot plate and D'Amour and Smith methods, FI-302 showed a potent analgesic effect, its efficacy being about 2 to 7 times greater than those of aminopyrine, mepirizole and tiaramide. On the other hand, in these methods, aspirin, ibuprofen and phenylbutazone had little or no effect. FI-302 showed a potent inhibitory effect on the vocalization response produced by electrical stimulation. Moreover, the analgesic effect of FI-302 after intracerebroventricular injection was about 58 to 278 times more potent than those of tiaramide and ibuprofen, and about 1/6 that of morphine. However, the analgesic effect of FI-302 was not antagonized by levallorphan. From these results, it appears that FI-302 has potent analgesic effects which may be produced by both peripheral and central mechanisms, but it is a non-narcotic compound. Consequently, FI-302 should be suitably applicable for clinical purposes.

Involvement of amygdaloid catecholaminergic mechanism in suppressive effects of desipramine and imipramine on duration of immobility in rats forced to swim

The suppressive effect of systemic injection of desipramine and imipramine on the duration of immobility in rats forced to swim was inhibited by 6-hydroxydopamine given into the medial amygdaloid nucleus as a pretreatment. Pretreatment with 5,7-dihydroxytryptamine given into the medial amygdaloid nucleus had no effect on the immobility-reducing effect of tricyclic antidepressants. The concentrations of catecholamines and serotonin in 6-hydroxydopamine- and 5,7-dihydroxytryptamine-pretreated rats, respectively, were significantly lower than those in the saline-injected rats. These results suggest that the suppressive effect of systemic injection of desipramine and imipramine on the duration of the immobility of rats forced to swim was mediated by the catecholaminergic but not the serotonergic mechanisms in the medial amygdaloid nucleus.

The site of action of morphine and indomethacin differs with electrical stimulation of cutaneous or tibial nerves in normal and adjuvant arthritic rats

Evoked potentials were recorded from the ventrobasal (VB) thalamus in normal and adjuvant arthritic rats anaesthetized with urethane (1200 mg/kg, i.p.). Effects of morphine and indomethacin on the evoked potentials elicited by transcutaneous electrical stimulation (TES) or tibial nerve electrical stimulation (TNES) were investigated. Morphine (1-3 mg/kg, i.v.) significantly depressed the potentials evoked by TES an TNES, in both groups. The magnitudes of the depressant effect of morphine were roughly equivalent, in each experiment. In normal rats, indomethacin (3-10 mg/kg, i.v.) significantly depressed the evoked potentials elicited by TES, but did not depress the evoked potentials elicited by TNES. In adjuvant arthritic rats, indomethacin (1-10 mg/kg, i.v.) depressed the evoked potentials elicited by TES and also, be it less readily, those elicited by TNES effects were more readily produced by TES than by TNES. These results suggest that the site of action of indomethacin differs in normal and adjuvant arthritic rats. The central antinociceptive action of indomethacin is clearly detectable in the presence of chronic inflammation. The antinociceptive action of morphine may reside in the neo-spinothalamic projection system, in both groups of rats.