Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

CD-1 mice received single intraperitoneal (IP) doses of caffeine-sodium benzoate (caffeine doses: 0, 20 and 40 mg/kg) followed by injections of alprazolampropylene glycol (0, 0.05, and 2 mg/kg, IP) to determine brain concentrations, effects on in vivo receptor binding of a specific high-affinity benzodiazepine receptor ligand [3H]Ro15-1788, and effects on motor activity over a 1-h period. A behavioral monitoring device, using infrared sensors, measured horizontal and ambulatory activity. Caffeine produced significant increases in all motor activity measures as compared to vehicle treatment, with low dose caffeine (with brain concentrations of 13 micrograms/g) stimulating activity to a greater degree than the high dose (with brain concentrations of 30 micrograms/g). The overall effect of caffeine on benzodiazepine receptor binding was not significant. Alprazolam significantly diminished motor activity and altered benzodiazepine receptor binding. Low dose alprazolam increased binding, while the high dose diminished it. Caffeine and alprazolam antagonized each other's behavioral effects in this study, but did not alter each other's uptake into brain. Alprazolam's antagonism of caffeine-induced motor stimulation was associated with decreases in receptor binding, whereas caffeine's reversal of alprazolam-induced motor depression was not associated with any changes in binding. The lack of a clear association between drug effects on benzodiazepine binding and on motor activity suggests that behavioral effects of caffeine and alprazolam may be mediated by other sites in addition to the benzodiazepine receptor.
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PMID:Separate and combined effects of caffeine and alprazolam on motor activity and benzodiazepine receptor binding in vivo. 216 93

The word "drug" in accordance with the definition given by the WHO means "any substance that, when taken into the living organisms, may modify one or more of its functions". This thus covers a wider field than the word "medicine" or "medicament". There are many substances which are capable of provoking anxiety and are very frequently consumed. According to recent publications the use and abuse of alcohol, cigarettes, heroin, cocaine, marihuana, and drugs such as sedatives (neuroleptics), caffeine, minor tranquilisers and other may provoke acute and chronic anxiety and depression. When confronted with anxiety states or depressive states, it is absolutely essential not to overlook the possibility that they may have been induced by a medicament or a drug which the patient has been using.
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PMID:[Anxiety and depression caused by side effects of drugs]. 216 87

The actions of adenosine in modulating amygdala kindling were examined using the stable adenosine analog 5'-N'-ethylcarboxamidoadenosine (NECA) and caffeine, an adenosine antagonist. Systemically administered NECA was found to significantly reduce the rate of postictal spiking and to significantly increase the duration of postictal EEG depression in amygdala kindled rats. In contrast, systemically administered caffeine significantly increased kindled seizure duration and reduced the duration of postictal EEG depression. Systemic administration of the methylxanthine derivative, 8-sulfophenyl theophylline (8-PST), failed to block the effects of NECA on kindling. Since systemically administered 8-PST blocks peripheral adenosine receptors, but has only limited CNS activity, the effects of NECA appear to be centrally mediated. These observations further demonstrate a role for adenosine in postictal phenomena and support the hypothesis that a release of endogenous adenosine contributes to the termination of ongoing seizure activity.
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PMID:Adenosine involvement in postictal events in amygdala-kindled rats. 227 40

1. To assess the mechanism(s) of the negative inotropic effects of amiodarone (AM), an effective anti-arrhythmic agent, the effects of AM on rested-state contraction (RSC) were studied in isolated ventricular papillary muscle from control (untreated) and AM-pretreated guinea-pigs. 2. The RSC was induced by stimulation, following a 30 sec- or 10 min-rest period. 3. The drug's effects were evaluated on an initial response (Ti) and steady-state response (Tss) of the RSC at the end of 1 min-stimulus train at 3.3 Hz. 4. In normal physiological solution, the magnitude of Ti was 2.1 times that of Tss in papillary muscles from untreated animals, but, 1.3 times, in AM-pretreated ones. 5. The effects of superfused AM (4.4 x 10(-5)M) were also evaluated in both muscle types. 6. The drug markedly decreased Ti and Tss in both control and AM-pretreated specimens. 7. However, the depression by superfused AM of RSC in control specimens was more likely to be marked than in AM-pretreated ones. 8. Further, verapamil and caffeine, which affect SR function, also depressed the RSC. 9. These results suggest that the negative inotropic actions of AM, at least in part, reflect a decrease in Ca2+ via Ca2+ channels and an impairment of Ca2(+)-sequestrating system.
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PMID:The inhibitory actions of amiodarone on rested-state contraction in isolated guinea-pig ventricular muscle. 227 88

Extracellular single-unit recordings were made from wide dynamic range neurones in the lumbar dorsal horn of anaesthetized or decerebrated cats. Vibration applied to the skin at a frequency of 80 Hz could evoke 3 distinct types of response--excitation, depression or a biphasic response consisting of excitation followed by depression. By applying vibration at different sites, a given neurone was found to show more than one type of response. Parametric studies of the depressant and biphasic responses were made because previous studies indicated that adenosine mediates the depression in these types of response. Thus, amplitude- and frequency-response relationships were determined at individual stimulation sites: amplitude was varied from 0.001 to 1.0 mm (frequency, 80 Hz) and the frequencies studied were 10, 20, 40, 80, 120 and 240 Hz (amplitude, 0.15 mm). Vibration at amplitudes greater than 0.15 mm caused a decrease in the rate of discharge during the period of stimulation, the magnitude of this decrease varying directly with amplitude; at amplitudes of 0.15 mm and less vibration had no statistically significant effect. With regard to the frequency-response relationship, a decrease in discharge rate occurred at frequencies of 120 and 240 Hz, with the more pronounced effect at 240 Hz; excitation occurred at 40 Hz and there was no statistically significant effect at other frequencies. Amplitude- and frequency-response relationships for the depressant and the biphasic responses were analyzed separately. In the case of depressant responses, the magnitude was monotonically related to the amplitude of stimulation and depression occurred only at frequencies of 80 Hz or greater, with higher frequencies being more effective. The biphasic responses appeared to consist of 2 subtypes termed biphasic-1 and biphasic-2 responses. For biphasic-1 responses, the amplitude- and frequency-response curves were similar to those of depressant responses. Biphasic-2 responses differed in that the response was biphasic when the stimulation frequency was 80 Hz or greater and the amplitude was 0.3 mm or more, yet, at lower frequencies and/or amplitudes vibration evoked excitation. The similarities in the amplitude- and frequency-response relationships of depressant and biphasic-1 responses raise the possibility that these responses might be mediated by a single class of primary afferent. Both depressant and biphasic responses were evoked when stimulation parameters (2 microns, 240 Hz) were used which selectively activate Pacinian corpuscle afferents. Depression with 240-Hz stimulation was attenuated by administration of caffeine (60 mg/kg i.v.) suggesting that the depressant and biphasic-1 responses may be mediated by afferents from Pacinian corpuscles.
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PMID:Physiological characteristics of responses of wide dynamic range spinal neurones to cutaneously applied vibration in the cat. 230 82

Evidence is presented for the hypothesis that the superficial sarcoplasmic reticulum (SR) of arterial smooth muscle functions as a "regulated buffer barrier" to Ca entry into the bulk of the myoplasm. Depletion of the intracellular Ca pool, which is sensitive to both norepinephrine (NE) and caffeine, decreases subsequent contraction due to high K+ depolarization. This effect is due to enhanced Ca accumulation by the SR, since it is not accompanied by a decrease in 45Ca influx. Using the Ca entry blockers D600 and La3+ to reduce tension and Ca influx during activation by NE and high K+ depolarization, we observed a threshold type of tension dependence on Ca influx. During the tonic contractile phases, the Ca influx threshold for NE-induced tension was much lower than that for high K+-increased tension. 10(-7) M NE, which discharged the SR by only 15%, caused a much smaller decrease in the Ca influx threshold for contraction, indicating that the degree of SR discharge is related to the depression of the threshold. Inositol-trisphosphate was shown to be capable of rapidly discharging Ca2+ from the SR in skinned arterial smooth muscle cells.
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PMID:The role of superficial SR in modulating force development induced by Ca entry into arterial smooth muscle. 243 11

Contribution of Ca2+-influx via the slow channel to generation of the transient inward current in guinea-pig ventricular muscles was studied using a single sucrose gap voltage clamp technique. The transient inward current (TI) was induced from superfusion of the preparations with the low-K+ (0 mM), high-Ca2+ (3.6 mM) solution. Application of 2 mM-CO2+ quickly and reversibly suppressed the TI amplitude to 25% of the control and delayed its peak timing to 153% during 10-20 min. Inhibition developed as quickly as Co2+ suppressed the slow inward current (Is), and its recovery took place without apparent time lag behind its effect on Is. The block of both TI and Is by Co2+ was antagonized by raising external Ca2+ to 7.2 mM. Removal of external Ca2+ caused a prompt suppression of both Is and TI. Application of 2 or 5 mM-procaine HCl produced a complete abolition of TI with a mild depression of Is. While 1 mM-caffeic caused a suppression of TI after a transient augmentation, 10 mM-caffeine completely eliminated it without abolishing Is. These results indicate that the Ca2+-influx through the slow channel acts not only to load the cell with those ions, but also to influence somehow the Ca2+-release from the stores under the Ca2+-overloaded conditions.
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PMID:Contribution of Ca2+-influx to generation of the transient inward current in guinea-pig ventricular muscles. 244 33

1. A series of related methylxanthines were studied for their effects on the kinetics of decay of end-plate currents (e.p.c.s) and miniature end-plate currents (m.e.p.c.s) at motor end-plates of the frog. 2. Isobutyl methylxanthine (IBMX, 50 microM-3 mM) produced a concentration-dependent depression of the peak e.p.c. and m.e.p.c. amplitude and a change in the kinetics of e.p.c. and m.e.p.c. decay from the normal single-exponential to a double-exponential function. Drug effects of this nature are generally attributed to open-channel blockade. 3. After wash-out of IBMX, the decay of the e.p.c. or m.e.p.c. was restored to a single-exponential function but with a significantly prolonged time constant. 4. Caffeine or theophylline derivatives (0.1-4 mM), during exposure to drug, produced effects similar to those observed after the application of IBMX; namely a prolongation of the time course of e.p.c.s and m.e.p.c.s without changing the single-exponential nature of the function. 5. Computer simulations were made of the m.e.p.c.s in IBMX. The effects of IBMX could be fitted to the sequential model of channel block only if the prolonged time constant observed upon wash-out was used for the rate constant of channel closure. Independent calculations of the rate constant of channel closure during IBMX application were in agreement with those measured during wash-out. 6. The theophylline derivative 8-phenyltheophylline, a selective adenosine receptor blocker with minimal effects on phosphodiesterase (PDE), increased the time constant of e.p.c. decay in a manner similar to theophylline and caffeine. Non-xanthine PDE inhibitors, either had no effect on m.e.p.c. decay (papaverine) or decreased the time constant of decay (RO 20-1724). It is thus unlikely that PDE inhibition is responsible for the post-junctional effects of IBMX. 7. IBMX (50 microM-2 mM) increased quantal ACh release in the virtual absence of extracellular calcium and also increased the efficacy of adenosine derivatives in inhibiting ACh release. Adenosine (10-100 microM) or 2-chloroadenosine (1-10 microM) had no effect on the time constant of e.p.c. decay nor did these adenosine receptor agonists alter the post-junctional actions of IBMX. The effects of IBMX on end-plate channel kinetics are thus not due to the blockade of adenosine receptors.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Independent control of channel closure and block of open channels by methylxanthines at acetylcholine receptors in frog. 245 Sep 93

The objective of these studies was to determine if methyl xanthines can be used to alter milk production or composition in ruminants by enhancing adipose tissue mobilization. Three trials were conducted, one with intravenous caffeine infusions, one with intramuscular caffeine injections, and one with intramuscular injections of 3-isobutyl 1-methyl xanthine. Results indicate that: 1) continuous intravenous infusions of caffeine (720 mg/d) may reverse the milk fat depression of intravenously infused glucose in dairy goats; 2) intramuscular injections of caffeine (200 mg twice daily) do not reverse the milk fat-depressing effects of pelleted dairy goat diets during the 4th mo of lactation; and 3) intramuscular injections of 3-isobutyl 1-methyl xanthine (50 mg twice daily) do not consistently affect milk production of early lactation dairy goats.
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PMID:Effects of caffeine and 3-isobutyl 1-methyl xanthine on caprine milk secretion. 245 50

The behavioral stimulant effects of xanthines, such as caffeine and theophylline, appear to involve blockade of central adenosine receptors. However, 3-isobutyl-1-methylxanthine (IBMX), a potent phosphodiesterase (PDE) inhibitor, produces behavioral depression. The effects of caffeine analogs on open field behavior of mice and potencies as antagonists of adenosine receptors and as inhibitors of three classes of brain PDE have been compared. 1,7-Dimethyl-3-propargylxanthine, 1,3,7-tripropargylxanthine, and 3,7-dimethyl-1-propargylxanthine, which have high affinity for adenosine receptors and weaker activity as PDE inhibitors, all increase behavioral activity. In contrast, 1,3,7-tripropylxanthine, a more potent inhibitor of the brain calcium-independent (Ca-indep) PDEs than 1,3,7-tripropargylxanthine, produces behavioral depression, even though both analogues are potent adenosine receptor antagonists. 7-Benzyl-IBMX, an active receptor antagonist and selective inhibitor of a brain calcium-dependent (Ca-dep) PDE, produces a slight behavioral activation. Xanthines that are potent adenosine receptor antagonists and relatively weak inhibitors of the Ca-indep PDEs reverse the depressant effects of N6-cyclohexyladenosine, while xanthines, such as 1,3,7-tripropylxanthine, that are potent inhibitors of the Ca-indep PDEs, do not. The results suggest that the behavioral effects of xanthines may be determined primarily by relative activity as adenosine receptor antagonists and as inhibitors of brain Ca-indep PDEs.
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PMID:Caffeine and theophylline analogues: correlation of behavioral effects with activity as adenosine receptor antagonists and as phosphodiesterase inhibitors. 245 42


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