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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Marijuana is widely used, yet few data concerning its actions combined with other drugs exist. Psychologic, respiratory and cardiovascular effects of delta9-tetrahydrocannabinol (THC), the active component of marijuana, combined with oxymorphone (OXM) or with pentobarbital (PBL), were studies in 15 healthy volunteers. Oxymorphone, 1.0 mg/70 kg, iv, caused sedation and ventilatory depression (minute ventilation: 24.9 plus or minus 11.9 SD to 14.1 plus or minus 4.9 1/min with PETCO2 held at 50 torr) in eight volunteers. TCH (27, 40, 60, 90, and 134 mug/kg, iv) increased sedation and further decreased ventilation with each TCH dose to 6.6 plus or minus 3.7 1/min after 134 mug/kg. The combination of OXM and THC decreased the CO2-ventilation slope from 2.23 to 0.88 1/min/torr. When THC, 134 mug/kg, was added to OXM, which alone caused no significant cardiovascular change, cardiac index (4.1 plus or minus 1.3 to 5.0 plus or minus 2.2 1/min/m-2) and heart rate (66 plus or minus 12 to 107 plus or minus 31 beats/min) significantly increased and total peripheral resistance (1,030 plus or minus 260 to 660 plus or minus 200 dynes-sec/cm-5) decreased. Heart rates exceeded 150 beats/min in two subjects after 27 and 134 mug/kg THC. Pentobarbital alone, 100 mg/70 kg, iv, caused no significant ventilatory or cardiovascular change. THC, after PBL pretreatment, induced hallucinations and anxiety in five of seven volunteers; four failed to complete all five doses of THC becuase of the severe psychologic effects. The combination of PBL and 40 to 134 mug/kg THC did not affect ventilation significantly. After PBL pretreatment, THC significantly increased heart rate (76 plus or minus 17 to 130 plus or minus 32 beats/min). Cardiac index also increased (3.8 plus or minus 0.8 to 5.6 plus or minus 1.9 1/min/m-2) and total peripheral resistance decreased (1,070 plus or minus 240 to 720 plus or minus 300 dynes-sec/cm-5). Three subjects developed heart rates esceeding 150 beats/min after 27, 27, and 90 mug/kg THC; in all three, heart rates fell from maximal value with a further dose of THC.
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PMID:Combination of delta9-tetrahydrocannabinol with oxymorphone or pentobarbital: Effects on ventilatory control and cardiovascular dynamics. 4 48

Pentobarbital in a dose of 3.5 mg/100 g b.w. did not suppress the high basal a.m. levels of plasma ACTH in adrenalectomized male rats. In both intact and adrenalectomized rats prior administration of the drug slightly depressed the rise in plasma ACTH induced by 2.5 min of ether inhalation, but this depression is of questionable statistical significance.
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PMID:The effect of pentobarbital on basal and ether-stimulated ACTH secretion in intact and adrenalectomized rats. 16 19

The respiratory effects of a new benzodiazepine, lorazepam, were compared to those of pentobarbital and pentazocine. Pentobarbital, 50 and 150 mg, produced respiratory depression, as did pentazocine, 30 mg intramuscularly. Lorazepam at 1.33 and 4 mg intramuscularly produced none.
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PMID:Respiratory effects of lorazepam, pentobarbital, and pentazocine. 23 7

The effects of ketamine and barbiturates (pentobarbital, thiopental, methohexital) were studied in an isolated rabbit Langendorff preparation. All agents tested depressed contractility. Ketamine, as well as the lipophilic barbiturates (thiopental, methohexital), caused a relatively greater depression at higher pacing rates such that the force-frequency relation was reversed. Pentobarbital did not reverse Bowditch. The effects of barbiturates on Bowditch correlated directly with lipid solubility, suggesting that their rate-related effects are due to perturbation of the membrane lipid bilayer. Disruption of hydrogen bands between polar membrane components may also be involved. The time course of the effect of thipental at high pacing rates was slower, both in onset and recovery, than at low rates. At a pacing rate of 1 Hz, maximal depression of contraction developed within 5 min. However, at 2.5 Hz, contractility continued to decline for up to 30 min. After 5 min of perfusion with thiopental, Bowditch was still positive, but by 30 min it was reversed. These temporal differences in thipental effects suggest that different mechanisms may dominate in the support of contractility at different ranges of heart rate.
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PMID:Effects of barbiturate anesthetics and ketamine on the force-frequency relation of cardiac muscle. 51 Apr

The toxicity of pentobarbital was examined in male Wistar rats pretreated with a non-toxic dose of imipramine (10 mg/kg, po). Pentobarbital (70 mg/kg, ip) lethality was enhanced up to 6 hr after imipramine administration, and pentobarbital (45 mg/kg, ip) sleeping time was prolonged up to 12 hr after imipramine. Physiological measurements showed that imipramine pretreatment 2 hr prior to pentobarbital (70 mg/kg, ip) enhanced barbiturate depression in mean blood pressure, oxygen consumption and respiration rate, but not in heart rate or back skin temperature. Analysis of brain radioactivity after [14C] pentobarbital indicated that these effects of imipramine were not solely the result of inhibition of liver metabolism.
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PMID:Imipramine enhancement of pentobarbital toxicity in rats. 93 31

Guinea pigs treated with a single s.c. injection of a slowly released morphine suspension (300 mg/kg) exhibited a quantifiable withdrawal syndrome after naloxone injection (0.01-10 mg/kg s.c.). Ileum removed from such animals responded to naloxone (1-300 ng/ml) by contracting. These contractions could be blocked by scopolamine or tetrodotoxin. Both the in vivo and in vitro responses were specific for the opiate-dependent state and were dependent on naloxone dose. Time courses of the development and decline of the two responses were similar. Weaker opioids, pentazocine and codeine, were less effective than morphine in producing a dependent state and sensitizing ileum to naloxone. 1-(-)-delta9-Tetrahydrocann abinol [1-(-)-delta9-THC] antagonized the effect of naloxone on ileum without affecting responses to acetylcholine. 1-(-)-delta9-THC produced a stereospecific, dose-dependent (1-10 mg/kg p.o.) inhibition of naloxone-precipitated withdrawal in guinea pigs and rats that was more complete than and different from that produced by sedatives. Pentobarbital inhibited withdrawal only at doses that produced ataxia. 1-(-)-delta9-THC had a biphasic effect on locomotor activity of guinea pig in the dose range that inhibited withdrawal, stimulation at 1 mg/kg and depression at 3 to 10 mg/kg. Our results suggest that cannabinoids may be useful in opiate detoxification. The inhibition by 1-(-)-delta9-THC of the action of naloxone in "dependent" ileum seems to be via reduction in acetylcholine release. Whereas the end result of 1-(-)-delta9-THC action in brain may not necessarily be a reduction in acetylcholine release as in ileum, the mechanism by which it produces this effect in the ileum model may explain its ability to antagonize withdrawal.
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PMID:Correlation between the in vivo and an in vitro expression of opiate withdrawal precipitated by naloxone: their antagonism by l-(-)-delta9-tetrahydrocannabinol. 98 78

The canine right atrium was perfused with arterial blood led from a carotid artery of the heparinized support dog and suspended in a bath filled with blood. In 5 non-spontaneously beating preparations, the frequency-force relationship was investigated by electric stimulation at a frequency range from 0.017 to 3 Hz. At a low frequency level, a large peak tension developed. At 0.5 Hz, minimum values of developed tension were obtained. At a range of 0.5-3 Hz, the developed tension increased with the frequency. Higher frequencies than 4 Hz usually caused pulsus alternans. The staircase phenomena were not influenced by treatment with propranolol or atropine. Therefore, there may be no participation of the autonomic nerve stimulation on the frequency-force relationship. Effects of pentobarbital, (+/-)-verapamil and manganese on the frequency-force relationship were investigated with both the blood-perfused, isolated atrium preparations and isolated ventricular preparations. Pentobarbital and manganese chloride produced a uniform depression of the developed tension at all frequencies but the depression with (+/-)-verapamil was greater at higher frequencies in both atrial and ventricular muscles.
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PMID:Effect of pentobarbital, verapamil and manganese on the frequency-force relationship of the isolated atrium and ventricle of the dog heart. 99 33

To ascertain whether neuroleptics act on the caudate nucleus itself, the effects of these compounds as well as other centrally acting drugs were examined in relation to caudate spindle and EEG arousal responses (sciatic nerve stimulation) in gallamine-immobilized cats. Haloperidol and chlorpromazine enhanced the caudate spindle at a dose which had no effect on the EEG arousal response. On the other hand, clozapine and a higher dose of chlorpromazine enhanced the caudate spindle, but depressed the arousal response. High frequency stimulation of the sciatic nerve suppressed the caudate spindle. Pentobarbital, biperiden and diazepam, while depressing the arousal response, caused an enhancement of the caudate spindle. Imipramine at a low dose had no effect on either response, whereas at a high dose this drug enhanced the caudate spindle with concomitant depression of the arousal response. From these results, it may be concluded that the enhancing action on the caudate spindle induced by haloperidol and a low dose of chlorpromazine is due to an increase in susceptibility of the caudate nucleus itself. In addition, it is suggested that depression of the activating system is involved in an appearance of the caudate spindle.
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PMID:Effect of psychotropic drugs on caudate spindle in cats. 100 8

Pentobarbital depressed macromolecular synthesis in Ehrlich ascites cells in vitro, and this depression was proportional to a decrease in oxygen consumption. However, survival time of animals bearing Ehrlich ascites cells was unaffected by pentobarbital. The acute toxicity of the drug was greatly enhanced by the presence of the tumor. Sleeping time was prolonged in mice carrying the following tumors: Ehrlich ascites, Sarcoma 180 ascites, and Yancy plasma cell solid. Seven-day Ehrlich ascites tumor-bearing animals treated with pentobarbital slept about three times longer than normal mice, but both groups awoke at the same plasma levels of the unbound drug. The plasma half-life of unchanged pentobarbital was about four times as long in tumor-bearing mice as it was in controls. No qualitative difference in catabolism other than rate was detected. Renal excretion of unchanged pentobarbital in tumor-bearing animals was 50% of control animals during the first 4 hr. In tumor-bearing mice the sleeping time of the nonmetabo ble barbiturate, barbital, was identical with that in normal animals. These data suggest that the tumor affected mainly pentobarbital metabolism. Tumor-bearing mice still responded to the pharmacological challenge of phenobarbital with the apparent induction of drug metabolizing enzymes. The prolonged pentobarbital sleeping time in tumor-bearing mice required the development of some type of tumor-host relationship.
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PMID:Physiological disposition of pentobarbital in tumor-bearing mice. 112 Mar 16

Eleven sheep were prepared with cannula guides directed toward four areas within the ventricular system to determine effective sites of action of chemicals which when injected into the cerebrospinal fluid produce changes in feeding behavior and temperature regulation. Pentobarbital, barbital, calcium chloride, and magnesium chloride elicited feeding in sheep when injected into the third ventricle or into the cerebral aqueduct; however, feeding response was less after injections into the latter. Pentobarbital and magnesium chloride elicited an increase in body temperature when injected into the third ventricle but not when injected into the cerebral aqueduct. Perfusions (push-pull) of the lateral and third ventricles with calcium chloride and magnesium chloride solutions (50 mM) resulted in feeding while similar perfusions of the fourth ventricle resulted in no response. Responses to lateral and third ventricular injections presumably involved effects on both anterior and posterior hypothalamic areas while injections into the cerebral aqueduct, due to the caudal flux of the cerebrospinal fluid, may have affected primarily only the posterior hypothalamus and more caudal structures. The feeding response probably resulted from depression of neural fibers which inhibit feeding.
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PMID:Feeding and temperature changes in sheep following injections of barbiturates, Ca-++, or Mg-++ into the lateral, third, or fourth ventricle or cerebral aqueduct. 112 57


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