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PubMed1988

Production and characterization of high-affinity monoclonal antibodies against morphine.

Twelve hybridoma cell lines producing MAbs against morphine were established by using morphine hemisuccinate-conjugated bovine serum albumin as an immunogen. The MAbs belonged to the IgG1 subclass with kappa- or lambda-chains. The association constants of the antibodies ranged from 4.6 x 10(8) to 4.7 x 10(10) (M-1). These antibodies revealed slightly different cross-reactivities with various agonistic opiates and antagonists. In general, the antibodies were strongly cross-reactive with the opiate agonists, codeine, ethylmorphine, dihydromorphine and dihydrocodeine, while their cross-reactivities with norcodeine and the opiate antagonists, naloxone and naltrexone, were weak. The cross-reactivities with dihydromorphinone, dihydrocodeinone, naloxone, naltrexone, dextromethorphan and homatropine varied from clone to clone. Interestingly, certain MAbs displayed weak but significant cross-reactivities with the synthetic opiate, meperidine. However, none of the antibodies was cross-reactive with the opioid peptides, beta-endorphin, Met-enkephalin, and D-Ala2-D-Leu5-enkephalinamide. Radioimmunoassay for morphine using one of the antibodies (MOR 131.5.13) was shown to be sufficiently sensitive (IC50 = 0.1 nM) for the purposes of forensic analysis of morphine. This set of monoclonal anti-opiate antibodies is assumed to be suitable for analyzing the structure-function relationship in the hapten-antibody interaction, since the antibodies revealed similar but not identical cross-reactivities with various morphine related compounds.

Animals↗

PubMed1982

Cardiovascular reflexes in conscious toads.

Methods used for implanting sensors and catheters in temporarily ether-anesthetized toads (Bufo paracnemis) are described. Following recovery it was found that distension of the pulmocutaneous arterial trunk and high frequency electrical stimulation of the laryngeal nerve of conscious toads induce an abrupt fall in arterial pressure accompanied or not by bradycardia or cardiac arrest. A brief suppression of throat movements may occur but this is not a constant finding. The response is blocked by atropine or methyl-homatropine and persists in animals with high spinal sectioning, thus indicating its cholinergic parasympathetic nature. However a certain amount of sympathetic inhibition is not ruled out. Perfusion of the artery with lobeline and electrical stimulation of the laryngeal nerve at low frequency (1/s) induces a rise in arterial pressure which is blocked by phentolamine. The hypertension is followed by enhancing of both throat oscillations and electromyographic discharges. The occurrence of chemoreceptors in the pulmocutaneous arterial wall in these animals is discussed. Blockage of the laryngeal nerve with lidocaine or perfusion of the pulmocutaneous arterial trunk with the same solution elicited a blood pressure rise, tachycardia and enhanced ventilatory movements. This was attributed to suppression of the baroreceptor tonus.

Animals↗

PubMed1992

The trigemino-pupillary reflex: a model of sensory-vegetative integration.

Trigeminal stimulation can induce pupillary changes. In vivo and in vitro studies have demonstrated that electrical impulses applied at the trigeminal level can provoke a miotic response, whose nature has been ascribed to the anti-dromic release of neuropeptides (substance P in particular). In order to better define the pupil response to trigeminal stimulation, we investigated the human pupil response to quantified (painless and painful) corneal stimuli by means of a combined (neurophysiological and pharmacological) technique. The response to corneal stimulation was bilateral, direct and consensual. It had a biphasic progression with an initial mydriasis (which directly correlated with the stimulus intensity), followed by a miotic phase. The mydriatic phase disappeared after thymoxamine application, while homatropine pre-treatment prevented occurrence of the miotic phase. The data obtained indicate that the pupillary response to corneal stimulation (trigemino-pupillary reflex) is a multisynaptic reflex with an afferent branch involving the trigeminal system, and an afferent branch involving both the sympathetic and the parasympathetic system. Other pathways, such as the SP-mediated release of acetylcholine, cannot be excluded. Thus the reflex appears to be a potentially useful tool for investigating pain/vegetative interactions in various clinical conditions. In turn, the description of its changes in pathologies characterized by a sympathetic/parasympathetic deficit or by a SP-ergic imbalance will allow us to better describe its inner mechanisms.

Adult↗

PubMed1995

Pupillary and cardiovascular responses to the cold-pressor test.

Little is known about the structures and mechanisms involved in the autonomic response to sensory and nociceptive stimulation. In this study, we recorded simultaneously pupil diameter, blood pressure, heart rate and pain levels during a cold-pressor test in 10 healthy subjects. The aim was to evaluate the different components of the Autonomic Nervous System involved in the response to a thermal-painful stimulus. A biphasic pupillary response was observed: an initial, short-lasting mydriasis, followed by a miotic phase, this latter characterized by rhythmic fluctuations of pupil diameter. The blood pressure response was monophasic with a moderate increase observed from the second minute of the test. Pain intensities remained stable on medium-high levels throughout the test. The topical application of thymoxamine and homatropine clarified some aspects of the pupillary response. The systemic administration of naloxone suggested a role of opiates in the modulation of pupillary and cardiovascular response to the cold-pressor test.

Administration, Topical↗

PubMed1995

Anterior segment ischemia after the Jensen procedure in a 10-year-old patient.

PURPOSE/METHODS: We recently encountered anterior segment ischemia in a young healthy girl with traumatic abducens nerve palsy after the Jensen procedure and ipsilateral recession of the medial rectus muscle. The patient was treated with topical dexamethasone and homatropine 2% and oral prednisone. RESULTS/CONCLUSION: The patient's condition improved, and six weeks postoperatively, visual acuity was 20/20. As this complication of anterior segment ischemia is potentially serious and unpredictable, we think that an alternative surgical approach should be used when treating patients with muscle palsies.

Abducens Nerve↗

PubMed2002

Topical ketorolac tromethamine 0.5% versus diclofenac sodium 0.1% to inhibit miosis during cataract surgery.

PURPOSE: To compare the effect of topical ketorolac tromethamine 0.5% solution and topical diclofenac sodium 0.1% solution on the inhibition of surgically induced miosis. SETTING: Tertiary care teaching hospital in South India. METHODS: Fifty-one patients were prospectively randomized to receive ketorolac 0.5% or diclofenac 0.1% at 3 intervals preoperatively. Patients with diabetes mellitus, pseudoexfoliation, or local pupil abnormalities were excluded from the study. Mydriatics comprising homatropine 1% plus phenylephrine 10% were instilled in all patients 1 hour before the peribulbar block at 5 intervals. Horizontal pupil diameters were obtained at the beginning of surgery, after capsulotomy, after intraocular lens (IOL) implantation, and at the end of surgery. RESULTS: The mean horizontal pupil diameter was 7.40 mm at the start of surgery in both groups. The ketorolac group showed a consistent trend toward larger pupil diameters at subsequent surgical intervals. Changes from baseline also indicated more significant inhibition of miosis in the ketorolac group. CONCLUSIONS: Topical ketorolac was a more effective inhibitor of miosis than topical diclofenac during extracapsular cataract extraction and IOL implantation. It also provided a more stable mydriatic effect throughout surgery.

Administration, Topical↗

PubMed1994

Use of topical nonsteroidal anti-inflammatory drugs in excimer laser photorefractive keratectomy.

Nonsteroidal anti-inflammatory drugs (NSAIDs) produce potent analgesic, antipyretic, and anti-inflammatory effects. We studied postoperative pain in 97 consecutive patients having photorefractive keratectomy (PRK) by an excimer laser with different topical NSAID protocols. Treatment with topical homatropine hydrobromide, either diclofenac sodium (Voltaren Ophthalmic) or ketorolac tromethamine (Acular), and a soft contact lens was most effective in achieving post-PRK analgesia. We also studied post-PRK myopic regression in 68 consecutive patients and found that flurbiprofen sodium (Ocufen), when added to topical steroid protocols, significantly reduced myopic regression for one year postoperatively more than steroids alone or steroids and diclofenac sodium. Diclofenac, used with topical steroids, had less of an additive effect on myopic regression than did flurbiprofen. Topical NSAIDs are useful adjuncts to PRK therapy, both to eliminate postoperative pain and to control post-PRK myopic regression.

Administration, Topical↗

PubMed1983

4-(Diphenylmethyl)-1-[(imino)methyl]piperidines as gastric antisecretory agents.

4-(Diphenylmethyl)-1-piperidinemethanimine (1) is a potent oral gastric antisecretory agent in rats but contains a strong anticholinergic component. Since a nonanticholinergic gastric antisecretory drug would be useful in the treatment of peptic ulcer disease, a program was initiated by us to find such an agent based on 1. Compound 1 contains structural elements common to the anticholinergics atropine and homatropine. Studies on the structure-activity relationships of these compounds and their derivatives have revealed certain modifications that diminish or abolish anticholinergic activity. The application of these modifications to the design of analogues of 1 afforded an antisecretory compound, 4-(diphenylmethyl)-1-[(octylimino)methyl]piperidine (3h, fenoctimine), which exhibited no anticholinergic activity. Fenoctimine is undergoing clinical trial as a gastric antisecretory drug.

Animals↗

PubMed2003

Structural basis of heroin and cocaine metabolism by a promiscuous human drug-processing enzyme.

We present the first crystal structures of a human protein bound to analogs of cocaine and heroin. Human carboxylesterase 1 (hCE1) is a broad-spectrum bioscavenger that catalyzes the hydrolysis of heroin and cocaine, and the detoxification of organophosphate chemical weapons, such as sarin, soman and tabun. Crystal structures of the hCE1 glycoprotein in complex with the cocaine analog homatropine and the heroin analog naloxone provide explicit details about narcotic metabolism in humans. The hCE1 active site contains both specific and promiscuous compartments, which enable the enzyme to act on structurally distinct chemicals. A selective surface ligand-binding site regulates the trimer-hexamer equilibrium of hCE1 and allows each hCE1 monomer to bind two narcotic molecules simultaneously. The bioscavenger properties of hCE1 can likely be used to treat both narcotic overdose and chemical weapon exposure.

Binding Sites↗

PubMed2003

Human carboxylesterase 1: from drug metabolism to drug discovery.

Human carboxylesterase 1 (hCE1) is a serine esterase involved in both drug metabolism and activation, as well as other biological processes. hCE1 catalyses the hydrolysis of heroin and cocaine, and the transesterification of cocaine in the presence of ethanol to the toxic metabolite cocaethylene. We have determined the crystal structures of hCE1 in complex with either the cocaine analogue homatropine or the heroin analogue naloxone. These are the first structures of a human carboxylesterase, and they provide details about narcotic metabolism in humans. hCE1's active site contains rigid and flexible pockets, explaining the enzyme's ability to act both specifically and promiscuously. hCE1 has also been reported to contain cholesteryl ester hydrolase, fatty acyl-CoA hydrolase and acyl-CoA:cholesterol acyltransferase activities, and thus appears to be involved in cholesterol metabolism. Since the enzyme may be useful as a treatment for cocaine overdose, and may afford protection against chemical weapons like Sarin, Soman and VX gas, hCE1 could serve as both a drug and a drug target. Selective hCE1 inhibitors targeted to several sites on the enzyme may also pave the way for novel clinical tools to manage cholesterol homoeostasis in humans.

Carboxylic Ester Hydrolases↗

PubMed1982

Latent dysautonomic pupillary lateralization in cluster headache. A pupillometric study.

Forty-five patients with cluster headache in the asymptomatic phase were studied by electronic pupillography, testing autonomic function of both pupils pharmacologically. Topical sympathetically-acting mydriatics, tyramine and cocaine and the cholinoceptor blocker, homatropine, induced defective mydriatic responses on the symptomatic side, indicating latent impairment of sympathetic function. The abnormality was found in interattack intervals of the cluster period or during intercluster phases. The tyramine test can be proposed for objective diagnosis of cluster headache. We postulate that cluster attacks are triggered and lateralized by a permanent latent unilateral sympathetic dysfunction. Lithium reduced the mydriatic response to tyramine of the pupil contralateral to the pain, thus restoring the equilibrium between both pupils; this therapy may correct the asymmetric sympathetic function by attenuating the activity in the asymptomatic side.

Adolescent↗

PubMed1991

The effect of tarsorrhaphy on normal healing of corneal epithelial defects in a rabbit model.

The presumed benefits of occlusive patching are patient comfort and enhancement of corneal healing. However, there is little experimental evidence to document a beneficial effect of eyelid occlusion on corneal healing. We produced corneal abrasions by mechanical debridement within a 4 mm trephine-marked area on 1 eye each of 23 New Zealand albino rabbits. Homatropine 5% solution and erythromycin ointment were instilled. Then we divided the animals into three groups. The abraded eyes of the first group (7 rabbits) were sutured shut by a temporary tarsorrhaphy. The eyes of the second group (7 rabbits) were left open until 12 h postinjury, when they were sutured shut in a similar fashion. The abraded eyes of the control group (9 rabbits) were left open for the entire observation period. We monitored fluorescein staining patterns of the epithelial defects photographically at a set focal length at 12-h intervals. By 48 h, corneal staining had resolved in 87% of eyes. We performed computerized planimetry on the photographs of wound size for each time point. There was no statistically significant difference in the rate of healing of corneal abrasions in the occluded versus of the unoccluded eyes.

Animals↗

PubMed2002

Mechanisms involved in the water intake-related pressor response in the rat.

OBJECTIVE: In this study we aimed to characterize and clarify the mechanisms involved in the acute blood pressure increase observed concomitantly with water intake in moderately dehydrated rats. DESIGN: Short-term water deprivation was employed as a model to induce controlled water intake to study concomitant cardiovascular responses in the rat. METHODS: Male Wistar rats were deprived of water for 18-24 h before the experiments and were allowed to drink for 20 s periods during the experimental session. During these periods water intake was accompanied by steady arterial pressure increases. This pressor response was unaffected by topical anesthesia of the oral cavity. Direct administration of water into the stomach did not cause pressor responses. The pressor response was not affected by bilateral adrenal demedullation or by pretreatment with diazepam, homatropine methyl bromide, d(CH2)5 Tyr(Me)AVP, losartan or RX821002. The pressor response was significantly reduced by ganglionic blockade with mecamylamine or pretreatment with the alpha1-adrenoceptor antagonist, prazosin. CONCLUSIONS: Our results show that: (1) short-term dehydration can be used as a model to study cardiovascular responses associated with water intake in rats; and (2) the sympathetic nervous system and vascular smooth muscle alpha1-adrenoceptors are involved in the pressor response to water intake by dehydrated rats.

Animals↗

PubMed2005

Dense membrane formation after combined phacoemulsification-trabeculectomy surgery.

A case is reported of formation of a dense intraocular membrane following combined phacoemulsification-trabeculectomy surgery. The membrane might have originated from a loose piece of pigment epithelium or might have resulted from dense pigment deposition on a postoperative pupillary membrane. Postoperative membranes have been reported particularly after combined procedures. A combination of intensive topical dexamethasone, homatropine and a Nd:YAG laser was used to speed resolution of the membrane.

Cataract↗

PubMed2005

Pressor and tachycardic responses evoked by microinjections of L-glutamate into the medial prefrontal cortex of unanaesthetized rats.

The ventral medial prefrontal cortex (vMPFC) is involved in central cardiovascular control. In the present study, we studied the cardiovascular effects of injections of L-glutamate into the vMPFC of unanaesthetized rats and the mechanisms of these effects. Male Wistar rats were used and L-glutamate was microinjected in the vMPFC in a final volume of 200 nL. Microinjections of L-glutamate (9, 27, 81, 150 or 300 nmol) caused long-lasting, dose-related pressor and tachycardic responses in unanaesthetized rats. No differences were observed among cardiovascular responses when L-glutamate was injected into the three sub-areas that comprise the vMPFC, namely the prelimbic, the infralimbic and the dorsal peduncular cortices. No responses were observed when the dose of 81 nmol of L-glutamate was microinjected into surrounding structures such as the cingulate cortex area 1, the corpus callosum and the tenia tecta, indicating a predominant action on the vMPFC. The cardiovascular response to L-glutamate into the vMPFC was blocked by intravenous pretreatment with the ganglion blocker pentolinium (10 mg/kg, i.v.) or the beta1-adrenoceptor antagonist atenolol (1.5 mg/kg, i.v.), supporting the involvement of the cardiac sympathetic nervous system in the response to L-glutamate. Pretreatment with the muscarinic antagonist homatropine methyl bromide (1 mg/kg, i.v.) reduced the latency to the onset of the pressor and tachycardic responses to L-glutamate injected into the vMPFC without significant effects on response duration or maximum effect. We conclude that stimulation of the vMPFC with L-glutamate caused pressor and tachycardic responses in unanaesthetized rats, responses which were dependent on cardiac sympathetic nerve activation and were potentiated by blockade of peripheral muscarinic receptors.

Animals↗

PubMed1963

SOME EFFECTS OF ATROPINE ON SMOOTH MUSCLE.

Contractions of the nerve-free smooth muscle of the chick amnion, either spontaneous or in response to electrical or mechanical stimuli, are potentiated by high conentrations (10(-5) g/ml.) of atropine sulphate. In addition hyoscine, homatropine, lachesine, propantheline bromide and atropine N-methyl and atropine N-butyl salts potentiate spontaneous activity in the amnion. The effects of atropine do not appear to depend on inhibition of cholinesterase; on labilization, stabilization or depolarization of the muscle cell membrane; or on an increase in metabolism. It is suggested that the effects are the result of blockade of the muscarinic acetylcholine receptors. The way in which this may facilitate the conducted response is discussed.

Amnion↗

PubMed1980

Radioimmunoassay for atropine and l-hyoscyamine.

A simple, specific and sensitive radioimmunoassay is described for atropine (dl-hyoscyamine) and l-hyoscyamine. Antiserum was obtained from rabbits immunized with an immunogen prepared by coupling l-hyoscyamine to human serum albumin. By using 3H-atropine as tracer, the assay can detect atropine and l-hyoscyamine concentratins down to 9 nmol/l(2.5 ng/ml) in a 0.1 ml serum or plasma sample. The recovery of atropine was near 100% when the drug was added at different concentrations to normal, pooled human plasma. Atropine and l-hyoscyamine are recognized equally well by the antibodies, but some other structurally related drugs (homatropine scopolamine) and atropine hydrolysis products (tropine, tropic acid) do not interfere. The usefulness of the method in pharmacokinetic studies was shown by assaying atropine concentrations in serial serum samples from two patients, who were given 1.3 mg atropine on connection with anaesthesia. A biexponential serum decay curve was demonstrated in both cases with a very rapid distribution phase (t 1/2 0.63 and 1.38 min.) and a much slower elimination phase (t 1/2 1.86 and 2.09 hrs.).

Adult↗

PubMed1966

The effect of orientation on the visual resolution of gratings.

1. Visual resolving power is known to be poorer for objects oriented obliquely as compared with horizontal and vertical orientations. Experiments were designed to evaluate the optical and neurophysiological factors involved.2. Gratings with a sinusoidal light distribution were generated on the face of an oscilloscope. Spatial frequency and contrast could be varied while keeping the mean luminance of the grating constant.3. Using a homatropinized eye with an artificial pupil and carefully corrected refraction, high resolution in the vertical and horizontal meridians as compared with the oblique meridians was found for gratings ranging in spatial frequency from 1 to 35 c/deg.4. It is concluded from the similar behaviour of low and high frequency gratings that neither focus errors nor optical aniseikonia can account for these findings.5. Additional proof that optical factors cannot significantly account for these preferred directions of resolution was obtained by forming interference fringes directly on the retina using a neon-helium laser as a coherent light source.6. Similar orientational changes in resolution were found by by-passing the dioptrics with interference fringes. It is concluded that the effect is due to some orientational inequality in the visual nervous system.

Accommodation, Ocular↗