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PubMedDate not supplied

Influence of dosage, consciousness, and nifedipine on the acute pressor response to intraperitoneally administered cadmium.

The acute pressor effect of intraperitoneally administered cadmium was explored over the dose range 0.015-2 mg/kg in both pentobarbital-anesthetized and conscious rats. The former first respondent at 0.031 mg/kg, and successive doublings of that dosage increased the highest pressures attained in a stepwise fashion until a dosage of 0.25 mg/kg, the maximally effective quantity, was reached. Arterial pressure did not rise in conscious rats until a dose of 1 mg/kg, which gave the maximum response within the range examined. Heart-rate changes with Cd were slight, and rarely significant at a given dosage, but pentobarbital invariably caused tachycardia. Anesthetized rats thus gave a graded response, while conscious animals reacted in an all-or-none fashion. The increased pressor responsiveness of rats under pentobarbital can not be ascribed to its cardiac parasympatholytic effects, since sensitivity was not conferred upon conscious rats when pretreated with atropine at a dose producing even greater tachycardia than that caused by pentobarbital. Nifedipine, which blocks calcium entry into smooth muscle cells, prevented the pressor response to cadmium when given as pretreatment and terminated an ongoing response when give intercurrently. Possible mechanisms to account for the observed behavior are considered.

Anesthesia↗
PubMed1998

Maternal exposure to prescription and non-prescription pharmaceuticals or drugs of abuse and risk of craniosynostosis.

BACKGROUND: The pre- and peri-natal drug exposures reported by women participating in a case-control study of children in Colorado were examined for association with infant craniosynostosis. METHODS: Mothers of case and control children underwent a standardized telephone interview and obstetric and newborn medical record review. The interview included questions on the use of prescription and non-prescription drugs, nutritional supplements, recreational and drugs of abuse. The mother's obstetric record was abstracted for information about pharmacologic agents taken before and during the antepartum period. RESULTS: There were no statistically significant risk ratios associating craniosynostosis with prenatal exposure to hydantoin, valproic acid, or cocaine. Mothers of four case children and one control child reported specific exposure to retinoic acid. There were no statistically significant increases in the odds ratio (OR) for any suture type among children exposed to hypoxigenic agents, sympathomimetic or parasympatholytic agents, or metal-containing agents. The OR was 1.87 (lower bound of the two-sided 95% test-based confidence interval (CI): 1.08) among children with sagittal/lambdoid suture synostosis who were exposed to nitrosatable drugs chlorpheniramine, chlordiazepoxide, and nitrofurantoin compared to controls. CONCLUSIONS: Certain nitrosatable drugs may be associated with increased risk of infant sagittal/lambdoid craniosynostosis. A possible mechanism related to ischaemia/reperfusion injury is suggested.

Case-Control Studies↗
PubMed1995

Premenstrual syndrome: a double-blind controlled trial of desipramine and methylscopolamine.

The aim of this study was to compare the effect of the selective noradrenergic reuptake inhibitor desipramine and methylscopolamine bromide, a parasympatholytic agent, on late luteal phase dysphoric disorder (LLPDD), or premenstrual syndrome (PMS), as defined in DSM-III-R. Fourteen patients with PMS were assessed both retrospectively and prospectively during premenstrual cycles. All met the DSM-III-R criteria for LLPDD. They received 3 months treatment each with both desipramine and methylscopolamine in random order using a double-blind cross-over design. PMS symptomatology was significantly reduced after treatment with desipramine and methylscopolamine bromide compared with baseline, but there was no significant difference between them in efficacy. There is evidence from this study that both anticholinergic and noradrenergic pathways may be involved in the genesis of PMS.

Adolescent↗
PubMed1982

Mydriatic effectiveness of dilute combinations of phenylephrine and tropicamide.

The effects of two solutions, each consisting of a combination of tropicamide and phenylephrine at lower than conventional concentrations, were studied in 79 students at Pacific University College of Optometry. Clinically effective diameters (CED's), measured when the eye was illuminated for direct ophthalmoscopy, were followed for 90 min after mydriatic instillation. Intraocular pressure (IOP), systolic arterial blood pressure (sBP), and the systolic BP/IOP ratio were also monitored for 90 min. Both combination A (0.25% tropicamide + 1.25% phenylephrine) and combination B (0.125% tropicamide + 2.0% phenylephrine) produced CED's as large as produced by 0.5% tropicamide in the opposite eye. By combining a low concentration of a sympathomimetic with a parasympatholytic agent, it is possible to achieve mydriasis superior to that produced by 0.5% tropicamide or 2.5% phenylephrine while reducing the risk of systemic or ocular side effects.

Adult↗
PubMed1984

Review of ciliary muscle effort in presbyopia.

Fincham's theory of presbyopia would require maximum ciliary muscle contraction to produce maximum accommodative response at all ages. The Hess-Gullstrand theory, however, would allow a maximum accommodative response with a decreasing ciliary muscle contraction as age increases leaving a reserve ability of ciliary muscle to contract with age. If Fincham's theory is correct, a mild parasympatholytic drug would produce a decrease in the amplitude of accommodation, a mild parasympathomimetic drug would produce an increase in the amplitude of accommodation, and the AC/A ratio would increase with age. The results of this study indicate that all three of these do occur and therefore support the Fincham concept of the cause of presbyopia.

Accommodation, Ocular↗
PubMed2005

Pharmacokinetics and pharmacodynamics in clinical use of scopolamine.

The alkaloid L-(-)-scopolamine [L-(-)-hyoscine] competitively inhibits muscarinic receptors for acetylcholine and acts as a nonselective muscarinic antagonist, producing both peripheral antimuscarinic properties and central sedative, antiemetic, and amnestic effects. The parasympatholytic scopolamine, structurally very similar to atropine (racemate of hyoscyamine), is used in conditions requiring decreased parasympathetic activity, primarily for its effect on the eye, gastrointestinal tract, heart, and salivary and bronchial secretion glands, and in special circumstances for a CNS action. Therefore, scopolamine is most suitable for premedication before anesthesia and for antiemetic effects. This alkaloid is the most effective single agent to prevent motion sickness. Scopolamine was the first drug to be made commercially available in a transdermal therapeutic system (TTS-patch) delivering alkaloid. Recently, pharmacokinetic data on scopolamine in different biozlogic matrices were obtained most efficiently using liquid chromatographic-tandem mass spectrometric (LC-MS/MS) or gas chromatography online coupled to mass spectrometry. Pharmacokinetic parameters are dependent on the dosage form (oral dose, tablets; parenteral application; IV infusion; SC and IM injection). Scopolamine has a limited bioavailability if orally administered. The maximum drug concentration occurs approximately 0.5 hours after oral administration. Because only 2.6% of nonmetabolized L-(-)-scopolamine is excreted in urine, a first-pass metabolism is suggested to occur after oral administration of scopolamine. Because of its short half-life in plasma and dose-dependent adverse effects (in particular hallucinations and the less serious reactions, eg, vertigo, dry mouth, drowsiness), the clinical use of scopolamine administered orally or parenterally is limited. To minimize the relatively high incidence of side effects, the transdermal dosage form has been developed. The commercially available TTS-patch contains a 1.5-mg drug reservoir and a priming dose (140 microg) to reach the steady-state concentration of scopolamine quickly. The patch releases 0.5 mg alkaloid over a period of 3 days (releasing rate 5 microg/h). Following the transdermal application of scopolamine, the plasma concentrations of the drug indicate major interindividual variations. Peak plasma concentrations (Cmax) of approximately 100 pg/mL (range 11-240 pg/mL) of the alkaloid are reached after about 8 hours and achieve steady state. During a period of 72 hours the plaster releases scopolamine, so constantly high plasma levels (concentration range 56-245 pg/mL) are obtained, followed by a plateau of urinary scopolamine excretion. Although scopolamine has been used in clinical practice for many years, data concerning its metabolism and the renal excretion in man are limited. After incubation with beta-glucuronidase and sulfatase, the recovery of scopolamine in human urine increased from 3% to approximately 30% of the drug dose (intravenously administered). According to these results from enzymatic hydrolysis of scopolamine metabolites, the glucuronide conjugation of scopolamine could be the relevant pathway in healthy volunteers. However, scopolamine metabolism in man has not been verified stringently. An elucidation of the chemical structures of the metabolites extracted from human urine is still lacking. Scopolamine has been shown to undergo an oxidative demethylation during incubation with CYP3A (cytochrome P-450 subfamily). To inhibit the CYP3A located in the intestinal mucosa, components of grapefruit juice are very suitable. When scopolamine was administered together with 150 mL grapefruit juice, the alkaloid concentrations continued to increase, resulting in an evident prolongation of tmax (59.5 +/- 25.0 minutes; P < 0.001). The AUC0-24h values of scopolamine were higher during the grapefruit juice period. They reached approximately 142% of the values associated with the control group (P < 0.005). Consequently, the related absolute bioavailabilities (range 6% to 37%) were significantly higher than the corresponding values of the drug orally administered together with water (range 3% to 27%). The effect of the alkaloid on quantitative electroencephalogram (qEEG) and cognitive performance correlated with pharmacokinetics was shown in studies with healthy volunteers. From pharmacokinetic-pharmacodynamic modeling techniques, a direct correlation between serum concentrations of scopolamine and changes in total power in alpha-frequency band (EEG) in healthy volunteers was provided. The alkaloid readily crosses the placenta. Therefore, scopolamine should be administered to pregnant women only under observation. The drug is compatible with nursing and is considered to be nonteratogenic. In conclusion, scopolamine is used for premedication in anesthesia and for the prevention of nausea and vomiting associated with motion sickness. Pharmacokinetics and pharmacodynamics of scopolamine depend on the dosage form. Effects on different cognitive functions have been extensively documented.

Humans↗
PubMed1979

Intranasal ipratropium: a new treatment for perennial rhinitis.

Eighty micrograms of the topically active parasympatholytic ipratropium were applied intranasally 4 times a day to 20 adult patients with perennial rhinitis and severe watery rhinorrhoea in a double-blind placebo controlled cross-over trial. There was a significant reduction in nasal hypersecretion during ipratropium treatment. Fourteen patients preferred the ipratropium period, 3 the placebo period and 3 had no preference. There were no adverse systemic or local effects. Ipratropium was effective also in patients resistant to glucocorticoids, sodium cromoglycate and antihistaminics. As the drug works immediately it can also be used before exposure to known provocating factors. It is concluded that continuous use of this new medication is of value in the management of severe rhinorrhoea in patients with perennial rhinitis, and that the occasional use is helpful in subjects with infrequent attacks of nasal hypersecretion.

Administration, Intranasal↗
PubMed1983

Ipratropium (Atrovent) in the treatment of vasomotor rhinitis of elderly patients.

Ipratropium is a parasympatholytic agent with high topical activity. The effect of intranasal ipratropium was studied in 34 patients who were over 60 years of age and who suffered from chronic watery vasomotor rhinorrhoea. The study was a double-blind cross-over placebo controlled trial. Trial parameters were: daily nasal symptom and side effect scores, nasal methacholine testing before and after treatment, and clinical evaluation. The active drug clearly reduced nasal discharge. Nasal methacholine testing showed reduction of nasal secretion after the active treatment period. The majority of the patients preferred the active drug to the placebo. Excessive drying of the nasal mucosa was the most common side effect. Ipratropium seems to have a beneficial effect on vasomotor rhinitis, which often is an irritating condition in elderly patients.

Administration, Intranasal↗
PubMedDate not supplied

Effects of mydriatics on intraocular pressure and pupil size in the normal feline eye.

OBJECTIVE: To determine the effect of various mydriatics (1% atropine, 1% cyclopentolate, 0.5% tropicamide, 10% phenylephrine) on intraocular pressure (IOP) and pupil size (PS) in normal cats. ANIMALS STUDIED: The mydriatics were tested in 10 adult ophthalmoscopically normal European Domestic Short-haired cats. Procedure Single-dose drug studies were divided into placebo (vehicle of phenylephrine), 10% phenylephrine, 0.5% tropicamide, 1% cyclopentolate and 1% atropine. After measurement of IOP and pupil size (PS) at 8 a.m. on the first day, one drop of the tested drug was applied to one randomly selected eye. The IOP and PS were measured for a minimum of 36 h until the pupil returned to pretest size. RESULTS: Ten per cent phenylephrine had no significant effect on IOP, and the effect on the pupil size was minimal (<or= 1 mm difference). One per cent atropine showed a maximal mean difference of 4.3 mmHg +/- 4.1 mmHg in IOP compared to the untreated eye. These differences were statistically significant at 1, 3, 6, 12 and 16 h post-treatment. At 1, 1.5 and 2 h after unilateral application of 1% cyclopentolate, the IOP in the treated eye was significantly higher than the IOP in the untreated eye with a maximal mean difference of 4.1 mmHg +/- 4.5 mmHg. With 0.5% tropicamide, IOP of the treated eye was significantly higher than IOP of the untreated eye at 1 and 1.5 h after treatment with a maximal mean difference of 3.5 mmHg +/- 3.3 mmHg. One per cent atropine caused the greatest increase in IOP, followed by 1% cyclopentolate and 0.5% tropicamide. The dilating effect of atropine, cyclopentolate and tropicamide lasted longer than the effect on intraocular pressure. CONCLUSIONS: The parasympatholytics 1% atropine, 1% cyclopentolate and 0.5% tropicamide caused a statistically significant elevation of IOP and produced mydriasis in the treated eye in normal cats, while the sympathomimetic 10% phenylephrine had no significant effect on IOP or pupil size.

Administration, Topical↗
PubMed1979

Urinary incontinence in the female. The value of detrusor reflex activation procedures.

One hundred consecutive female patients with urinary incontinence were investigated with CO2 cystometry including detrusor reflex activation procedures such as postural change and ability to suppress self-induced detrusor contractions. Detrusor hyperreflexia was seen in 20 patients during bladder filling in the supine position, and in an additional 35 patients after detrusor reflex activation procedures. Four different types of detrusor hyperreflexia are described based on the cystometric findings. In 38 patients treated with parasympatholytics, 66% showed a good result independent of the type of detrusor hyperreflexia.

Carbon Dioxide↗
PubMed2005

Dobutamine-induced bradycardia in a dog.

An otherwise healthy 8-year-old neutered male, mixed breed dog was anesthetized for surgical removal of multiple uroliths. Pre-anesthetic medication was midazolam, glycopyrrolate, and morphine. Anesthesia was induced with propofol and maintained with isoflurane in oxygen. One hour after induction, the patient moved and propofol was administered. Subsequently, the patient developed hypotension. Dobutamine administered at this time produced a rapid and profound decrease in heart rate that was treated successfully with atropine. The bradycardia in this case may be the result of the Bezold-Jarisch reflex, an intracardiac parasympathetic nervous reflex. Discontinuation of dobutamine and/or administration of a parasympatholytic drug should be performed if bradycardia occurs during dobutamine infusion.

Anesthesia↗
PubMed1964

A COMPARISON OF IMIPRAMINE, CHLORPROMAZINE AND RELATED DRUGS IN VARIOUS TESTS INVOLVING AUTONOMIC FUNCTIONS AND ANTAGONISM OF RESERPINE.

Seven structurally-related compounds consisting of three antidepressant drugs (imipramine, desmethylimipramine and amitriptyline), three tranquillizing agents (promazine, chlorpromazine and chlorprothixene) and a hybrid, desmethylpromazine, have been examined in a series of tests involving autonomic functions and antagonism of reserpine. Activities of the compounds in antagonizing reserpine-induced ptosis in rabbits and prolongation of alcohol hypnosis in mice give good correlation with their clinical actions, whilst their activities in augmenting excitation of rats by amphetamine and yohimbine toxicity in mice, and in reversing reserpine-induced bradycardia in rats offer further evidence for drug-induced sensitization to adrenergic or tryptaminic mechanisms, which is not however specific for antidepressant agents. No evidence has been obtained to indicate that a central parasympatholytic action is an important component of the antidepressant activity of imipramine and related drugs.

Alcoholic Intoxication↗
PubMed1976

Effect of SAS (a new 10-N-acylaminophenothiazine) on gastric secretion and ulceration in rats.

The antiulcer and antisecretory activity of 2-chloro-10-[4'(N-beta-hydroxyethyl) piperazinyl-1'] acetylphenothiazine (SAS) has been investigated. At 10 and 20 mg/kg (s.c.) the drug was found to possess potent antigastric secretory and antiulcer activity (both in shay and stress ulcers) and did not exhibit any peripheral parasympathetic blocking activity. The pronounced antispasmodic activity of SAS was nonspecific rather than a specific parasympatholytic effect.

Acetylcholine↗
PubMed1985

Pharmacological studies on the regulation of N-acetyltransferase activity and melatonin content of the pineal gland of the Syrian hamster.

Thus far, all attempts to stimulate melatonin synthesis by beta-adrenergic receptor agonists in the Syrian hamster pineal gland have failed. Neither a wide range of dosages of isoproterenol (0.5 mg/kg to 24 mg/kg), nor prolonged treatment with norepinephrine, the natural neurotransmitter, increased N-acetyltransferase (NAT) activity or melatonin production. In the present study, the administration of isoproterenol at night was likewise ineffective in advancing or enhancing the normal nightly melatonin peak. Also, we did not find a delayed effect 7 or 8 h after the administration of the drug. Furthermore, we tested the idea of coneurotransmitters such as octopamine or dopamine being possibly necessary for stimulation, but could not find any effect of these substances on melatonin synthesis. In addition, a parasympatholytic agent, atropine, did not increase the responsiveness to sympathomimetic agents. Administration of a phosphodiesterase inhibitor was also ineffective in stimulating NAT activity. On the other hand, isoproterenol did retard the drop in NAT and melatonin after lights-on at night, indicating that beta-receptors are involved in maintaining elevated melatonin levels.

Acetyltransferases↗
PubMed1975

Atropine sensitivity of the rat urinary bladder during nerve degeneration.

The pressure response of the rat urinary bladder to electrical stimulation of the pelvic nerve at a low stimulation frequency was found to be almost completely atropine resistant. However, the response to stimulation of the degenerating pelvic nerve 20-30 h after section of the nerve postganglionically using maximal stimulation frequency was totally abolished by atropine or the parasympatholytic agent Hoechst 9980. The responses were not affected by hexamethonium or dihydroergotamine, but were potentiated by eserine. The non-adrenergic portion of the bladder response to stimulation of the degenerating hypogastric nerves was also abolished by atropine or Hoechst 9980. It is concluded that the transmitter activating the detrusor muscle at stimulation of the pelvic nerve or the non-adrenergic part of the hypogastric nerve probably is acetylcholine.

Amides↗
PubMed1976

Blood flow changes in the submaxillary gland of the rat on parasympathetic and sympathetic nerve stimulation.

Blood flow and secretion from the submaxillary gland of the rat was recorded. Stimulation of the chordalingual nerve evoked vasodilatation which was little, it at all, decreased after administration of atropine. The secretion evoked on parasympathetic nerve stimulation was greatly reduced but not totally abolished by parasympatholytic agents. Stimulation of the cervical sympathetic trunk evoked secretion, which was mediated both via alpha and beta-adrenoceptors and vasoconstriction which was abolished by dihydroergotamine, and thus seemed to be mediated via alpha-adrenergic receptors. After alpha-adrenoceptor blockade vasodilatation was seen on sympathetic nerve stimulation. This was abolished by the beta-adrenoceptor blocking agent propranolol.

Acetamides↗
PubMed1967

Effects of physalaemin on some exocrine secretions of dogs and rats.

1. Physalaemin, an endecapeptide recently found in the skin of the South American amphibian Physalaemus fuscumaculatus, possesses, besides a marked hypotensive action and a powerful sialogogic activity, also a stimulant activity on other exocrine secretions.2. Exocrine structures which were more potently stimulated by the peptide were lacrimal glands and exocrine pancreas. In the anaesthetized dog the threshold lacrimatory dose was 0.05-0.3 mug/kg; in the rat the threshold dose was 2.5-5 mug/kg. The minimum active dose on exocrine pancreas of the dog was 0.05-0.5 mug/kg.3. Physalaemin did not influence the gastric acid secretion of the dog at the maximum tolerated dose (40 mug/kg). Gastric acid secretion of the rat was stimulated very little if at all.4. In the dog the peptide caused some changes in the bile flow which were connected more with contracture of the gall-bladder than with a true secretory stimulant activity. In the rat the peptide was completely ineffective.5. The results obtained after administration of sympatholytic and parasympatholytic agents suggest that the action of the peptide is at least partly independent from the autonomic nervous system.

Journal Article↗
PubMed1977

Dilating dangerous pupils.

Altogether 85 eyes from patients at risk to the development of closed-angle glaucoma were dilated with either parasympatholytic or sympathomimetic drugs. Of 21 eyes dilated with cyclopentolate 1/2%, 9 developed angle closure and a significantly raised pressure at some stage during dilatation and subsequent miosis. Of 58 eyes dilated with tropicamide 1/2%, 19 developed angle closure and a significantly raised pressure during dilatation. Treatment with intravenous acetazolamide and pilocarpine rapidly returned pressure to normal levels. Six eyes that had previously had a positive provocative test with simultaneous pilocarpine and phenylephrine were safely dilated with phenylephrine alone. Subsequent miosis with pilocarpine produced closed-angle glaucoma in all eyes. The significance of these observations is explained and discussed, and it is suggested that high-risk eyes should never be dilated with cyclopentolate. Tropicamide is safe if elementary precautions are observed. Safest of all, however, is phenylephrine-induced mydriasis and subsequent miosis with thymoxamine drops 1/2%.

Acetazolamide↗