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At least 127 records · Page 7Linked to original sources

PubMed2000

Muscarinic mediation of the urethro genital reflex in spinal cord-transected rats.

The effects of muscarinic receptor stimulation were tested on the urethro genital reflex (UGR) in anesthetized and spinal cord-transected rats. Drugs were applied directly to the spinal cord. The electromyographic activity (EMG) of the bulbospongiosus (BS) muscle was used for recording UGR. In six animals BS as well as soleus, posterior biceps or peroneus tertius muscle EMG was recorded simultaneously. Muscarine (5, 10, 20, 50 and 100 microg) was applied in 22 animals after cutting L6-S1 dorsal roots. Some observations were made on another six animals, to which an extensive bilateral dorsal rhizotomy (L3-S2) was performed. Rhythmic bursts of similar frequency and size to those seen during UGR were found in BS muscle a few minutes after muscarine application. No rhythmic bursting was found on the hindlimb muscles, but exclusively on BS muscles. The effects of homatropine (25, 50, 100 and 200 microg), an acetylcholine muscarinic receptor antagonist, were tested in 21 rats after UGR was elicited three times at low stimulation intensity (7 mm Hg). Homatropine produced two effects: (i) A significant increase in the latency of UGR. (ii) A facilitation of UGR inhibition. In view of these results it can be speculated that muscarinic receptor stimulation is involved in the elicitation of UGR.

Animals↗

PubMedDate not supplied

Possible non-muscarinic miotic action of echothiophate iodide in humans.

The proposed non-muscarinic pupillary action of echothiophate iodide (EI) was investigated in humans. In 10 healthy volunteers the variations of the pupillary area, induced by EI eye drops, were evaluated by using an electronic pupillometer. When instilled alone, as well as after homatropine, EI caused pupillary constriction. The reduction of the homatropine-induced mydriasis by EI was not accompanied by any increase in the almost abolished pupillary response to light, thus excluding that an enhancement of the parasympathetic activity contributes to pupillary constriction. These findings suggest a non-muscarinic component in the EI-induced miosis, the nature of which remains to be elucidated.

Adolescent↗

PubMed1981

Effect of antimuscarinic agents on the contractile responses to cholinomimetics in the rat anococcygeus muscle.

1 The effects of antimuscarinic agents alone and in the presence of neostigmine on the contractile responses to exogenously applied cholinomimetics or (-)-noradrenaline were studied in the rat anococcygeus muscle.2 Atropine (1 x 10(-9) -1 x 10(-6)M) alone, in the presence of hexamethonium (1 x 10(-4)M), or phentolamine (1 x 10(-6)M), inhibited responses to acetylcholine but not to (-)-noradrenaline. The inhibitory effect with the higher concentrations of atropine (1 x 10(-8) - x 10(-6)M), was seen as an increase in the slopes of the concentration-response curves. Atropine (1 x 10(-8)M) alone inhibited the responses to methacholine and carbachol without altering the slopes of the concentration-response curves.3 Homatropine (1 x 10(-6)M) alone had no effect on responses to (-)-noradrenaline and inhibited responses to acetylcholine and methacholine. The inhibitory effect on responses to acetylcholine but not to methacholine, included an increase in the slopes of the concentration-response curves.4 Neostigmine (1 x 10(-6)M) alone had no effect on responses to (-)-noradrenaline and potentiated responses to acetylcholine and methacholine. The potentiating effect included an increase in the slopes of the concentration-response curves.5 In the presence of neostigmine (1 x 10(-6)M), atropine (1 x 10(-9)M - 1 x 10(-6)M) caused a parallel concentration-dependent shift of the concentration-response curves to acetylcholine. The pA(2) values, in the presence of neostigmine, were independent of the concentration of atropine and of the agonist (acetylcholine, methacholine, or carbachol) used. In the presence of neostigmine (1 x 10(-6)M), homatropine (1 x 10(-6)M) also failed to alter the slopes of the concentration-response curves to acetylcholine and was approximately 100 times less potent than atropine as an antimuscarinic agent.6 These results illustrate that, in the rat anococcygeus muscle, it is necessary to inhibit acetylcholinesterase before determining the relative potencies of antagonists at muscarinic receptors.

Animals↗

PubMed1996

Topical analgesia for superficial corneal injuries.

OBJECTIVE: To assess the analgesic effects of a topical non-steroidal anti-inflammatory agent, flurbiprofen 0.03%, during healing after superficial corneal injuries. METHODS: 401 patients treated for corneal abrasion in a five month period were randomly allocated to one of four treatment groups: polyvinyl alcohol alone (control), homatropine 2%, flurbiprofen 0.03%, or homatropine 2% followed by flurbiprofen 0.03%. Treatments were given for 48 h. Ocular pain was recorded on a visual analogue scale by the patients over the first 24 h, and use of oral analgesics was also recorded. Usable responses were received from 224 patients (55.8%). RESULTS: Patients treated with flurbiprofen had significantly lower pain scores for the 24 h duration of the study than controls (P < 0.05). CONCLUSIONS: Flurbiprofen eye drops provide more effective pain relief than traditional treatments for superficial corneal injuries.

Administration, Topical↗

PubMed1993

Muscarinic receptors in the aortae of normo- and hypertensive rats: a binding study.

The muscarinic receptors in the aorta of the normo- and hypertensive rats were characterised with tritiated acetylcholine (3H-ACh) and various muscarinic receptor antagonists. The binding of 3H-ACh to the endothelial membranes of the normotensive Wistar Kyoto rats (WKY) and the spontaneously hypertensive rats (SHR) was displaceable by nanomolar range of scopolamine but only by micromolar range of atropine and homatropine. The reverse was observed with the muscle binding sites, i.e. the 3H-ACh was displaceable by nanomolar range of atropine and homatropine but only by micromolar range of scopolamine. Pirenzepine and 4-diphenyl-acetoxy-N-methyl-piperidine metobromide (4-DAMP) displaced the binding of 3H-ACh from both tissues in the nano to micromolar range, with the displacement from the endothelial binding sites occurring at lower concentration range of the ligands. The apparent IC50 values of both compounds for the smooth muscle were 9 and 16 times greater than those for the endothelial binding sites respectively. When saturated with guanylyl-imididiphosphate (GppNHp), conversion of high to low-affinity binding site occurred in both tissues of the WKY but only in the smooth muscle of the SHR. GppNHp had no apparent effect on the binding of 3H-ACh to the endothelial binding sites confirming that the high-affinity site for 3H-ACh was missing in the endothelium of the SHR.

Acetylcholine↗

PubMed1975

[Cycloplegia and residual accommodation (author's transl)].

The cycloplegic effect of 1% Atropine Sulphate, 2% Homatropine Hydrobromide and 1% Cyclopentholate (Cyclolat) were compared on 8 to 10 year-old children with hyperopic accommodation and partial accommodation squint. The objective refraction was measured by skiascopy and with Hartinger's refractometer, and these two values were compared. The distant-vision correction, and also the near-vision correction needed so that Table 2 of Pursch's Tables could be read, were measured. Atropine showed itself to be the most effective cycloplegic agent. With atropine cycloplegia was attained in 46.77% - shown by a necessary near-correction of +2 dioptres, or less. In 27.42% the correction was +1.5 dioptres. With homatropine a correction of +2 dioptres or less occurred in 82.14%, after Cyclogyl in 72.34%. Better cycloplegia could be reached, if before the test correcting spectacles are worn. Only with repeated refraction-tests to overcome accommodation spasm could one succeed in finding the complete hypermetropic state -- even with the help of a not very demanding cycloplegic agent like atropine. Cyclogyl was found to be the most suitable agent here.

Accommodation, Ocular↗

PubMedDate not supplied

Identification and estimation of the levo isomer in raw materials and finished products containing atropine and/or hyoscyamine.

The belladonna alkaloids atropine sulfate and hyoscyamine sulfate, occasionally used as anticholinergic and antimuscarinic agents, have identical molecular formulas but different stereo configurations. Hyoscyamine sulfate contains almost 100% of the levo isomer, whereas atropine sulfate is composed of equal parts of dextro and levo isomers. It is believed that the therapeutic properties of these alkaloids are due exclusively or primarily to the levo isomer. Currently available methods determine only the total amount of atropine (hyoscyamine) sulfate. A method has been developed and is reported for the identification and estimation of the levo and dextro isomers of atropine and hyoscyamine. Reference solutions are prepared in methanol at the following weights per 100 mL: 8.0 mg atropine sulfate; 4.0 mg hyoscyamine sulfate; 7.0 mg scopolamine hydrobromide; and 10.0 mg homatropine methylbromide. Samples of raw materials are similarly prepared in methanol, commercial products are also extracted or diluted with methanol, and solutions are filtered. Liquid chromatography is used for separations on a 25 cm Chirobiotic T2 column. The mobile phase is prepared by mixing 3.0 mL acetic acid and 2.0 mL triethylamine with 1000 mL methanol. The injection volume is 100 or 200 microL; the flow rate is about 0.35 mL/min. Fluorescence detection is at 255 nm excitation and 285 nm emission. Scopolamine hydrobromide and hyoscyamine eluted after 20 and 60 min, respectively. Atropine sulfate generated 2 peaks after 60 and 65 min. Homatropine methylbromide also produced 2 peaks after 70 and 85 min. Samples tested in this study included raw materials and commercial tablets or injections containing belladonna alkaloids. In all cases, the percentage calculated was that of the levo isomer relative to the total amount of atropine (hyoscyamine) present.

Atropine↗

PubMed1987

Interaction of himbacine with carbachol at muscarinic receptors of heart and smooth muscle.

The interaction of himbacine with carbachol was studied and compared with that of homatropine in guinea-pig atria and rat stomach fundus. Himbacine was a competitive antagonist of carbachol in both preparations. In atria, himbacine had similar affinity for the muscarinic receptors associated with force (pA2 = 8.33) and rate of contraction (pA2 = 8.42). In stomach, himbacine had a pA2 value of 7.29 which corresponds to a 10-fold less affinity than for atria. In contrast, homatropine had similar affinities for muscarinic receptors in stomach (pA2 = 7.13) and for those in atria mediating force (pA2 = 7.21) and rate (pA2 = 7.07) responses. These results indicate that himbacine distinguishes between cardiac and smooth muscle muscarinic receptors whereas it is unable to distinguish between possible subtypes of cardiac receptors associated with force and rate responses.

Alkaloids↗

PubMedDate not supplied

[Endocrinological and neurophysiological modifications in a case of atropinic delusional state].

In this case report, we observed a delirium probably owing to toxic effects of homatropine eye drops. We reproduced this syndrome and we reversed it with physostigmine salicylate as an antidote. We observed a decrease of cortisol at 9.00 a.m. and impairment of regional cerebral blood flow with increase in the previous right side. The unusual susceptibility of this patient to the anticholinergic effect of homatropine is perhaps related to a preexisting mild cognitive defect possibly related to a cholinergic neurotransmitter deficit.

Aged↗

PubMed1979

[Cycloplegia with cyclopentolate for testing-refraction of children (author's transl)].

A comparative study of the cycloplegic effect of 1% cyclopentolate and atropine or homatropine was done by means of Lindner's method of retinoscopy. In 53% of 1.5- to 6-year-old strabismic patients the hypermetropic refraction was higher (average 0.6 dpt) under the use of atropine, and in 27% of 6- to 11-year-old children cyclopentolate was more effective than homatropine (average 0.5 dpt). Therefore, atropine should be used for children with convergent squint up to 6 years, in order to get full correction of hypermetropia. In other cases cyclopentolate is preferable because of its rapid and strong efficiency of brief duration.

Accommodation, Ocular↗

PubMed1979

The failure of conventional drug therapy in the management of infantile colic.

During five years, 97 young infants with colic were studied. One of us (J. C. O'D.) compared homatropine methylbromide plus phenobarbital in a 20% alcohol solution, and all of the individual components of that solution, to see which was most effective in the symptomatic relief of colic. Regardless of the child's age on entry into the study, conditions in no treatment group improved more rapidly than in those treated with a placebo.

Colic↗

PubMed1975

Analysis of Duboisia myoporoides R. Br. and Duboisia leichhardtii F. Muell.

Duboisia samples were analyzed for scopolamine and hyoscyamine using GLC, by a slope ratio method, and by methods employing homatropine, tetraphenylethylene, and phenylacetyltropine as internal standards. Limits of precision were determined by the inverse prediction method. Phenylacetyltropine was the preferred internal standard. The alkaloids were silanized with either hexamethyldisilazane or N,O-bis(trimethylsily)acetamide to prevent dehydration to the apo forms. Samples from a commercial bale of Duboisia myoporoides were assayed. The alkaloid content varied considerably, depending on the sample position within the bale.

Atropine↗

PubMed1976

Analysis of alkaloid mixtures by charge-transfer complexation.

Binary mixtures of weak and strong UV-absorbing alkaloids were analyzed by a charge-transfer spectrophotometric method, utilizing iodine in ethylene dichloride as the acceptor. In the uncomplexed form, the strong absorbing alkaloid (papaverine, quinine, ergotamine, or reserpine) was measured at a wavelength where there was no interference from weak absorbers (at 335, 332, 315, or 300 nm, respectively). The weak absorbing alkaloid (ephedrine, codeine, atropine, or homatropine methylbromide) was determined by computing its contribution to the total charge-transfer band at 295 nm where absorbance was linearly additive for mixtures. The greater increase in the original epsilon-values of the weak absorbers upon complexation with iodine relative to the corresponding increase in the epsilon-values of the strong absorbers led to good recoveries even at the low dose ratios of the weakly absorbing, and often more potent, alkaloids.

Alkaloids↗

PubMed1981

Application of one-phase end-point change system in two-phase titration to amine drug analysis.

A titration method was developed for the determination of diphenhydramine, quinine, neostigmine, sparteine, strychnine, homatropine, atropine, physostigmine, and procaine in aqueous solution. Tetraphenylborate was used as a titrant with tetrabromophenolphthalein ethyl ester as an indicator in the presence of organic solvent. End-point detection was based on the color change of the indicator in the organic phase without movement of the indicator from one phase to the other.

Amines↗

PubMed1989

Acute closed-angle glaucoma after arteriovenous fistulas.

Unilateral secondary acute closed-angle glaucoma was associated with a ciliochoroidal detachment in two patients. One patient, aged 17 years, had an orbital arteriovenous fistula. The other patient, aged 73 years, had a dural arteriovenous fistula that originated from branches of the right internal maxillary artery. In each patient there was increased intraocular pressure, a moderately shallow central anterior chamber, and a flat peripheral anterior chamber. The ciliochoroidal detachment was postulated to displace the iris-lens diaphragm, resulting in the closed angle. Closure of the orbital fistula in the 17-year-old patient reduced the ciliochoroidal detachment and relieved the glaucoma, but visual acuity was reduced to 20/200. The glaucoma in the 73-year-old patient was relieved with topical instillation of timolol 0.5%, homatropine 5%, and systemic administration of acetazolamide. The fistula closed spontaneously, with relief of other ocular signs of the arteriovenous fistula.

Acute Disease↗

PubMed1995

Buspirone, but not sumatriptan, induces miosis in humans: relevance for a serotoninergic pupil control.

BACKGROUND AND OBJECTIVE: Drugs that act on the serotoninergic system have been shown to influence the pupil size. However, the 5-hydroxytryptamine (5-HT) receptor type or subtype that affects pupil diameter has not been defined in humans. With a placebo-controlled, double-blind randomized design, we investigated in healthy volunteers the effect on pupil size of buspirone and sumatriptan, which mainly act on 5-HT1A- and the 5-HT1-like receptors, respectively. METHODS: The pupil area was measured by means of a videopupillometer before and after a single oral administration of placebo or of three different doses of active drugs. Heart rate and arterial blood pressure were recorded after pupil area measurement. RESULTS: Buspirone (5, 10, and 20 mg) caused a dose-dependent miosis. Sumatriptan (50, 100, and 200 mg) did not affect the pupil size. Twenty milligrams of buspirone reduced the mydriasis induced by pretreatment with homatropine eyedrops. A 20 mg dose of buspirone reduced blood pressure without change in heart rate, whereas buspirone, at doses lower than 20 mg, and sumatriptan did not affect heart rate and blood pressure. CONCLUSIONS: This study suggests that buspirone, but not sumatriptan, the selective agonist of 5-HT1-like receptors, causes miosis in humans by activation of 5-HT1A receptors, possibly located in the central nervous system where they inhibit iris sympathetic pathways. Measurement of pupil size seems to provide a valuable and sensitive index of 5-HT1A receptor function in humans.

Administration, Oral↗

PubMed1983

Structure-activity requirements for hypotension and alpha-adrenergic receptor blockade by analogues of atropine.

The hypotensive action of various antimuscarinic compounds structurally related to atropine was studied in conscious, unanesthetized rats. The alpha-adrenolytic activity of these agents was assessed both in vivo (blockade of norepinephrine-induced pressor response) and in vitro (displacement of [3H]WB-4101 binding). Benztropine, homatropine and hyoscyamine caused hypotension and produced alpha-adrenergic receptor blockade similar to atropine. Other analogues were either inactive (atroscine, scopolamine, tropic acid and tropine) or evoked nonspecific changes in blood pressure and lacked alpha-adrenolytic activity (benactyzine, eucatropine, methylatropine, methylhomatropine and methylscopolamine). Based on these data, we propose the following structure-activity relationship for hypotension and alpha-adrenolytic activity: (a) the tropine moiety is inactive unless it is attached to another group by an ester linkage, (b) chemical modification of the tropine moiety, including quaternization, decreases potency, (c) the d-stereoisomer appears to be more potent than the corresponding 1-form.

Acetylcholine↗

PubMed1989

Characterization of the antimuscarinic effect of heptane-1,7-bis-(dimethyl-3'-phthalimidopropyl ammonium bromide).

The effect of heptane-1,7-bis-(dimethyl-3'-phthalimidopropyl ammonium bromide) (C7/3'-phthalimidopropyl), an alkane bisquaternary compound with muscarinic receptor blocking activity was studied in guinea-pig atria and ileal longitudinal muscle. C7/3'-phthalimidopropyl was a more potent inhibitor of atrial muscarinic receptors, the cardioselectivity being ca. 32-fold. Previous studies in guinea-pig atria have shown that its antimuscarinic effect was of an allosteric nature. In ileal longitudinal muscle C7/3'-phthalimidopropyl (3 to 100 microM) appeared to behave in a competitive manner towards carbachol but the combination of atropine or homatropine with C7/3'-phthalimidopropyl produced a supra-additive inhibitory effect on the responses to carbachol. In both atria and ileal longitudinal muscle homogenates, C7/3'-phthalimidopropyl also slowed the dissociation rate of [3H]QNB suggesting an allosteric mechanism. In binding studies using either [3H]QNB or [3H]oxo-M, C7/3'-phthalimidopropyl recognized two binding sites in atria and ileum. In both tissues, C7/3'-phthalimidopropyl bound with high affinity (ca. 30-70 nM) to 60-85% of the sites and with low affinity (ca. 1-9 microM) to the remaining sites. Correlation of these affinity constants with the dissociation constants obtained in functional studies in the two tissues is discussed.

Animals↗