The interaction of dopamine, cocaine, and cocaethylene with ethanol on central nervous system depression in mice.

The interactions between dopamine, cocaine, cocaethylene, and ethanol were studied in Swiss-Webster mice. The loss of the righting reflex (LORR) was used as a measure of CNS depression. Animals were injected intraperitoneally (IP) with ethanol (4.0 g/kg). which caused a LORR. Immediately upon regaining of the righting reflex, mice were injected intracerebroventricularly (ICV) with saline, dopamine (0.1, 0.5, or 1.0 mumol/kg), cocaine (1, 15, or 25 mumol/kg), or cocaethylene (1, 15, or 25 mumol/kg). In the presence of systemic ethanol, all three compounds produced CNS depression in a dose-dependent manner. The dopamine D2-receptor antagonist sulpiride and the D1-receptor antagonist fluphenazine were given acutely ICV with dopamine in the presence of systemic ethanol to examine whether these antagonists could block the return to the LORR produced by dopamine. Sulpiride, however, actually enhanced the interaction between ethanol and dopamine in a dose-dependent manner as measured by the LORR; fluphenazine neither blocked nor enhanced the effect of dopamine in the presence of systemic ethanol. In addition, these antagonists had no effect on cocaine- and cocaethylene-induced CNS depression in the presence of systemic ethanol. The results of this study showed that the neurotransmitter dopamine and both cocaine and cocaethylene can promote further CNS depression in the presence of systemic ethanol, and that dopamine was significantly more potent than cocaine and cocaethylene as measured by the return to the LORR.

Glycine enhances the central depressant properties of ethanol in mice.

The interaction between ethanol and glycine in the central nervous system was investigated in male Swiss-Webster mice. The loss of the righting reflex (LORR) was used as a measure of central nervous system depression. Mice were injected with ethanol (4.0 g/kg, IP), causing an ethanol-induced LORR. Immediately after the animals regained the righting reflex from ethanol administration, they received an intracerebroventricular (ICV) injection of saline or glycine (1, 15, 25, or 50 mumol/kg) in a volume of 5 microliters. Upon ICV injection of glycine, the mice lost the righting reflex once again. This effect of glycine in the presence of ethanol occurred rapidly and in a dose-dependent manner. Glycine induced a return to the LORR of 12.6 +/- 0.7, 24.5 +/- 1.3, 32.8 +/- 2.0, and 46.8 +/- 4.5 min when doses of 1, 15, 25, and 50 mumol/kg, respectively, were injected. D-Serine (15, 25, or 50 mumol/kg), an amino acid precursor of glycine, was injected (ICV) after the animals regained the righting reflex following ethanol injection (IP). Serine caused a return to the LORR of 0.5 +/- 0.5, 6.0 +/- 1.0, and 6.5 +/- 0.9 min when doses of 15, 25, and 50 mumol/kg, respectively, were injected. Strychnine was used to attenuate the ability of glycine and serine to cause a return to the LORR in the presence of ethanol. Strychnine, a competitive antagonist of glycine, significantly reduced the ability of glycine and serine to enhance the depressant action of ethanol.(ABSTRACT TRUNCATED AT 250 WORDS)

Determination of cocaine usage in pregnant women by a urinary EMIT drug screen and GC-MS analyses.

In mothers who had no prenatal care and in their newborns, the presence of cocaine and benzoylecgonine (BE) was determined in urine, hair, and meconium. Samples of urine and hair were obtained from pregnant women who entered the hospital for delivery. Cocaine usage was assessed by a urinary enzyme-multiplied immunoassay technique (EMIT) and by gas chromatography-mass spectrometry (GC-MS). GC-MS was used to detect the presence of cocaine and BE in maternal urine and hair and in meconium and hair obtained from their newborns. In this study of 40 women, the EMIT assay for urinary BE identified 17 (42.5%) of the women as having used cocaine. Of these 17 women, all of their newborns were exposed to cocaine during gestation, based on the analysis of neonatal hair and meconium for cocaine or BE. From the maternal samples that were assayed for cocaine and BE by GC-MS, it appears that hair analysis identified the most cocaine users (70%) of the 40 women who participated in the study. When GC-MS was used to analyze the various samples from mothers and their newborns, 80% of the neonates showed exposure to cocaine. This study shows that women with no prenatal care who have a positive urinary drug screen by EMIT for BE have exposed their newborns to cocaine. The data from pregnant women with a negative drug screen for BE show that 52.2% of their newborns had prior fetal exposure to cocaine.

The presence of cocaine and benzoylecgonine in rat cerebrospinal fluid after the intravenous administration of cocaine.

Cocaine hydrochloride, in doses of 0.5, 1.0, 2.0 and 4.0 mg/kg, iv, was administered to male Sprague-Dawley rats. Cerebrospinal fluid (CSF) was collected from the cisterna magna over a 20 min period and blood samples were obtained at 20 min after cocaine administration. In addition, blood samples for the 1 mg/kg dose of cocaine were collected at 2, 10, 20 and 30 min following drug injection. Gas chromatography/mass spectrometry was used for the analysis of cocaine and its metabolites in plasma and CSF. The disappearance of cocaine (1 mg/kg) from the plasma exhibited first order kinetics with a half-life of 18.11 +/- 3.22 min. Cocaine and benzoylecgonine were found in CSF and the concentrations of cocaine and benzoylecgonine increased in CSF as the doses of cocaine were increased. CSF flow rates were not altered by the iv administration of cocaine or benzoylecgonine. The CSF-to-plasma ratios for cocaine were quite similar to each other over the dosage range of cocaine that was administered; however, the CSF-to-plasma ratios for benzoylecgonine decreased as the concentrations of benzoylecgonine increased in plasma and CSF. When benzoylecgonine (2 mg/kg, iv) was given, the compound was detected in CSF indicating that benzoylecgonine can enter into the central nervous system from the peripheral blood. This investigation shows that cocaine and benzoylecgonine can be assayed in CSF and that the plasma levels of these compounds correlate with their concentrations in CSF.

The accumulation and disappearance of cocaine and benzoylecgonine in rat hair following prolonged administration of cocaine.

Hair samples were obtained at various time periods from male Sprague-Dawley rats following the injection of cocaine hydrochloride in doses of 5, 10, and 20 mg/kg, ip, for 28 days. Hair samples were also taken continually after the dosing was stopped until the presence of cocaine and benzoylecgonine were no longer detected in hair. Cocaine and benzoylecgonine in hair and plasma were analyzed by gas chromatography/mass spectrometry. Both cocaine and benzoylecgonine were found in hair samples 4 days after the initiation of cocaine administration. When cocaine dosing was stopped after 28 days, approximately 25 to 30 days were required for cocaine and benzoylecgonine to disappear from rat hair in the group of animals that received the highest dose of cocaine. The disappearance of cocaine and benzoylecgonine followed first-order kinetics. The mean rate constant and mean half-life for cocaine disappearance from hair were 0.212 +/- 0.005 day-1 and 3.31 +/- 0.09 days, respectively, and the mean rate constant and mean half-life for benzoylecgonine disappearance from hair were 0.098 +/- 0.006 day-1 and 6.90 +/- 0.28 days, respectively. The mean plasma concentrations of cocaine on Day 25 for the 5, 10, and 20 mg/kg doses of cocaine were 508 +/- 42, 852 +/- 95, and 2027 +/- 75 ng/mL, respectively, and the mean plasma benzoylecgonine levels for the 5, 10, and 20 mg/kg doses of cocaine were 49.9 +/- 7.0, 103.3 +/- 9.3, and 191.0 +/- 16.0 ng/mL, respectively. There was a positive correlation between the doses of cocaine hydrochloride administered and the plasma levels of both cocaine and benzoylecgonine. This study showed that cocaine and benzoylecgonine can be measured in rat hair following the administration of cocaine and that it was possible to correlate the concentrations of cocaine and benzoylecgonine found in hair with the doses of cocaine that were administered.

Intravenous infusions of nitroprusside, dobutamine, and nitroglycerin are compatible.

It is now customary practice to couple separately metered infusions via a manifold to a common catheter that enters the patient. Nitroprusside, however, is considered incompatible with all other medications. Critically ill patients who require multiple infusions of vasoactive and inotropic medications would benefit if physicians had additional information regarding compatibility of nitroprusside with other commonly used infusions. Utilizing high-performance liquid chromatography, the authors investigated the physical and chemical compatibility of nitroprusside, dobutamine, and nitroglycerin in solutions of 5% dextrose or 0.9% NaCl at clinically relevant concentrations. All drugs were present within the guidelines of the U.S. Pharmacopeia (+/- 10%) over 24 h in NaCl, but nitroglycerin degraded over 24 h when the three drugs were mixed in dextrose. We recommend diluting these medicines in NaCl when mixtures of them would exist for greater than 4 h.

Extracellular sodium is required for methacholine-induced secretion of mucus glycoconjugates from canine tracheal explants.

Extracellular sodium is known to influence secretion by certain secretory cells, possibly by mobilizing calcium from cellular stores or by altering intracellular pH via regulation of a Na(+)-H+ antiport system. Using canine tracheal explants, we determined whether agents which alter sodium fluxes are capable of modulating basal or cholinergically-induced secretion of mucus glycoconjugates. Methacholine, a cholinergic agonist, increased mucus secretion from explants incubated in the presence or absence of calcium, but had no effect on secretion when incubated in sodium-deficient media, indicating (a) that cholinergically-induced secretion can be mediated by mobilization of cellular calcium and (b) that extracellular sodium was required for this stimulatory effect. Several agents which increase intracellular sodium were tested for their effect on mucus secretion. Ouabain, a sodium pump inhibitor, and veratridine, a sodium channel activator, did not significantly affect control or methacholine-induced secretion; gramicidin, a sodium ionophore, also had no effect on basal release. Tetrodotoxin, a sodium channel inhibitor, was also without effect on basal or methacholine-stimulated mucus release. Agents which alter intracellular pH were also examined for their effects on basal or methacholine-induced glycoconjugate secretion. Amiloride, which decreases intracellular pH by inhibiting Na(+)-H+ exchange, produced a 19 per cent increase in basal secretion (not statistically significant), but had no effect on methacholine-induced secretion. An agent, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), which decreases intracellular pH by inhibiting HCO3(-)-Cl- exchange, elicited decreases in both basal and methacholine-induced secretion, but the inhibition did not reach statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

The modulatory effects of leukotrienes C4 and D4 on methacholine- and substance P-induced salivary secretion in rats.

Although certain prostaglandins have been found to be inhibitory to nerve-evoked salivary flow, little is known of the effects the leukotrienes on salivary secretion. It was the purpose of this investigation to examine the effects of leukotrienes C4 (LTC4) and D4 (LTD4) on salivary secretion in the rat, using methacholine or substance P to induce basal secretion, and to test whether or not the observed effects of these eicosanoids were receptor-mediated by using the leukotriene receptor blocker FPL-55712. Methacholine (3 x 10(-4) M), or substance P (1 x 10(-6) M) was infused intra-arterially to stimulate secretion and saliva was collected separately from the parotid gland and the submandibular gland of anesthetized rats. LTC4 and LTD4 (each at 1 x 10(-9) to 1 x 10(-6) M) were found to reduce methacholine- and substance P-induced salivary flow in a dose-related manner. Salivary protein concentration and amylase activity were not significantly altered by the leukotrienes; however, arginine-esterase activity, stimulated by substance P, was increased by both leukotrienes. FPL-55712 (1 x 10(-8) M) was shown to reduce the inhibitory effects of LTC4 and LTD4, suggesting the involvement of leukotriene receptors for these agents in their action.

Effects of substance P and substance P antagonists on rat salivary secretion.

The intra-arterial infusion of substance P produced dose-related responses of both parotid and submandibular salivary secretion in anesthetized rats. The substance P-induced secretion in both glands was inhibited by the substance P analogues [D-Arg1, D-Trp7.9, Leu11]-substance P and [D-Arg1, D-Pro2, D-Trp7.9, Leu11]-substance P, but not by [D-Pro2, D-Trp7,9]-substance P. The profiles of protein and calcium levels obtained with substance P-induced salivary secretion for both glands were similar to those produced by acetylcholine stimulation and were not altered by the substance P analogues.

Cyclic nucleotides fail to affect mucus glycoconjugate secretion from canine tracheal explants.

Canine tracheal explants, incubated overnight with [3H]glucosamine, elicited an enhanced secretion of ethanol-precipitated [3H]labelled glycoconjugate when challenged with methacholine, 10 microM. Neither the beta-adrenoceptor agonist isoprenaline, 10 microM, nor the phosphodiesterase inhibitor theophylline, 10 mM, had any significant effect on glycoconjugate secretion. Dibutyryl cyclic AMP, 1 mM, and dibutyryl cyclic GMP, 1 mM, alone or in combination with theophylline, 10 mM, were devoid of activity on unstimulated or methacholine-stimulated tracheal explants. The calcium ionophore A23187, 10 microM, stimulated [3H]glycoconjugate secretion from each of the tissues tested; however, the cyclic nucleotides failed to modify this response. These data indicate that the cyclic nucleotides play little, if any, role in mucus glycoconjugate secretion by the canine trachea.

The release of slow-reacting substance of anaphylaxis from guinea pig lung: effects of calcium antagonists.

The effects of three calcium antagonists, verapamil, lanthanum, and 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate (TMB-8) were studied on the release of slow-reacting substance of anaphylaxis (SRS-A) from ovalbumin-sensitized chopped guinea pig lung parenchyma in calcium-containing and calcium-free media. The SRS-A levels (mean +/- SEM) obtained from tissues incubated in normal and calcium-free Krebs-bicarbonate buffer were 51 +/- 8 (N = 19) and 21 +/- 4 (N = 14) U/mL, respectively. TMB-8 (0.1-10 microM), a reported intracellular calcium antagonist, reduced antigen-stimulated SRS-A release from lung tissue incubated in calcium-containing, but not calcium-free, medium; A23187-induced SRS-A release from normal guinea pig lung was not significantly altered by TMB-8 at concentrations up to 10 microM. Verapamil and lanthanum consistently reduced SRS-A release only at high concentrations (100 microM and 1mM, respectively). The quantities of SRS-A released from lung tissue incubated in the presence of verapamil in normal medium were similar to those obtained in calcium-free medium. Tissues incubated in the presence of potassium chloride (60 and 100 mM) did not release significant quantities of SRS-A, and release which did occur was not blocked by verapamil, suggesting that antigen-induced SRS-A release is not dependent on membrane depolarization and that verapamil was not exerting inhibition via blockade of voltage-dependent calcium channels. These data suggest that although intracellular calcium is important for the regulation of SRS-A secretion from guinea pig lung tissue, extracellular calcium is necessary for optimal release of SRS-A.

The calcium dependency of mucus glycoconjugate secretion by canine tracheal explants.

Canine tracheal explants, incubated overnight with [14C]-glucosamine, elicited an enhanced secretion of ethanol-precipitated 14C-labelled glycoconjugate when challenged with methacholine, 10 microM. Explants were rendered deficient in total calcium content and unresponsive to methacholine, 10 microM, by incubating them in calcium-free medium for 18 to 22 h; however, the secretory response to the cholinergic agonist was restored with the addition of calcium to the medium. A dose-response relationship resulted when explants were challenged with methacholine in nutrient medium containing varied calcium concentrations (0.45 to 7.2 mM); alterations in the calcium concentration in the absence of methacholine had no significant effect on the basal secretion of 14C-labelled glycoconjugate. The calcium-selective ionophore A23187, 10 microM, stimulated [14C]-glycoconjugate secretion and induced the most significant effect in the presence of nutrient medium containing calcium. Verapamil, 10 microM, a calcium-entry blocker failed to inhibit basal or stimulated [14C]-glycoconjugate secretion; however, the intracellular calcium antagonist TMB-8, 10 to 100 microM, inhibited methacholine-induced [14C]-glycoconjugate secretion in a dose-dependent manner. These data suggest that respiratory mucus secretion is a calcium-dependent process and that intracellular calcium is more vital than extracellular calcium in supporting this phenomenon.

A small animal model study of perlite and fir bark dust on guinea pig lungs.

Fir bark (Abies) and perlite (noncrystalline silicate) dusts have been reported to cause pulmonary disease in humans. Guinea pigs were exposed to either fir bark or perlite dust in a special chamber. Severe pathologic changes occurred in the lungs, consisting of lymphoid aggregated and a perivascular inflammatory response. Both dusts caused similar changes although one was vegetable (fir bark) and the other mineral (perlite). Fir bark and perlite dust appeared to be more than just nuisance dusts.

Effects of calcium and verapamil on vesicourethral smooth muscle of rabbits.

Isolated smooth muscle strips from the rabbit bladder body, bladder base, and proximal urethra were contracted with ionic calcium (Ca2+) alone and with the calcium-selective ionophore A23187, acetylcholine, norepinephrine, adenosine triphosphate (ATP), and direct electrical stimulation. The effects of Ca2+ and the calcium entry blocker verapamil on spontaneous muscle activity and on contractions induced by these agonists were examined. Ca2+ -free Tyrode's solution and verapamil, 1 x 10(-7)M and above, relaxed all of the vesicourethral smooth muscle strips. In addition verapamil, 1 x 10(-8) to 1 x 10(-6) M depending on the particular stimulant employed, noncompetitively inhibited smooth muscle contractions elicited by Ca2+, acetylcholine, norepinephrine, ATP, and direct electrical stimulation. It was concluded that transmembrane Ca2+ influx was important not only in the maintenance of tone and spontaneous phasic muscle activity, but also for the activation of contractions induced by all of the stimulants tested. The data also suggest that intracellular Ca2+ fraction(s) participate in the contractile responses to acetylcholine and norepinephrine challenge, but not to contractions evoked by ATP or electricity.

The effects of indomethacin and prostaglandins E2 and F2 alpha on canine tracheal mucus generation.

The effects of prostaglandins on respiratory smooth muscle are well known; however, their role in mucus generation has received little attention. This investigation was undertaken to study the actions of prostaglandin E2 (PGE2) and prostaglandin F2 alpha (PGF2 alpha) on secretion and synthesis of respiratory mucus glycoproteins. The method employed canine tracheal explants; radiochemical precursors were used in the culture media for labelling and quantitation of the secreted glycoproteins. Glycoprotein secretion was not significantly influenced by PGE2 (1 x 10(-10) to 1 x 10(-3) M) or PGF2 alpha (1 x 10(-8) to 1 x 10(-4) M). However, PGF2 alpha (1 x 10(-3) M and 1 x 10(-2) M), significantly stimulated glycoprotein secretion. The mechanism may have involved a contractile effect on myoepithelial cells of the submucosal glands. Synthesis of glycoproteins was significantly inhibited by PGF2 alpha (1 x 10(-5) M), indomethacin (1 x 10(-6) M), and the combination PGF2 alpha (1 x 10(-5) M)/indomethacin (1 x 10(-6) M). PGE2 (1 x 10(-5) M) and arachidonic acid (1 x 10(-5) M) were without effect. These data suggested that indomethacin inhibited glycoprotein synthesis by a mechanism other than an action on prostaglandin synthetase. In addition, because these agents inhibited synthesis of glycoproteins which were labeled with 3H-glucosamine, 35S-sulfate, and 14C-serine, it appears that their action was primarily upon synthesis of the protein core.