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PubMed2004

Subunit rotation models activation of serotonin 5-HT3AB receptors by agonists.

The N-terminal extracellular regions of heterooligomeric 3AB-type human 5-hydroxytryptamine receptors (5-HT3ABR) were modelled based on the crystal structure of snail acetylcholine binding protein AChBP. Stepwise rotation of subunit A by 5 degrees was performed between -10 degrees and 15 degrees to mimic agonist binding and receptor activation. Anticlockwise rotation reduced the size of the binding cavity in interface AB and reorganised the network of hydrogen bonds along the interface. AB subunit dimers with different rotations were applied for docking of ligands with different efficacies: 5-HT, m-chlorophenylbiguanide, SR 57227, quinolinyl piperazine and lerisetron derivatives. All ligands were docked into the dimer with -10 degrees rotation representing ligand-free, open binding cavities similarly, without pharmacological discrimination. Their ammonium ions were in hydrogen bonding distance to the backbone carbonyl of W183. Anticlockwise rotation and contraction of the binding cavity led to distinctive docking interactions of agonists with E129 and cation-pi interactions of their ammonium ions. Side chains of several further amino acids participating in docking (Y143, Y153, Y234 and E236) are in agreement with the effects of point mutations in the binding loops. Our model postulates that 5-HT binds to W183 in a hydrophobic cleft as well as to E236 in a hydrophilic vestibule. Then it elicits anticlockwise rotation to draw in loop C via pi-cation-pi interactions of its ammonium ion with W183 and Y234. Finally, closure of the binding cavity might end in rebinding of 5-HT to E129 in the hydrophilic vestibule.

Amino Acid Sequence↗

PubMed1988

A transient array of parallel microtubules in frog eggs: potential tracks for a cytoplasmic rotation that specifies the dorso-ventral axis.

The dorsoventral axis of the frog embryo is specified by a rotation of the egg cytoplasm relative to the cortex. When eggs undergoing the cortical/cytoplasmic rotation were examined by immunocytochemistry and electron microscopy, an extensive array of parallel microtubules was found covering the vegetal hemisphere of the egg. The microtubules were 1-3 microns deep from the plasma membrane and were aligned parallel to the direction of rotation. They formed at the start of rotation and disappeared at its completion. Colchicine and uv irradiation, inhibitors of the rotation, prevented the formation of the parallel microtubules. Based on these properties, we suggest that the parallel microtubules serve as tracks for the cortical/cytoplasmic rotation which specifies the dorsoventral axis of the embryo.

Animals↗

PubMed1976

Phencyclidine-induced rotational behavior in rats with nigrostriatal lesions and its modulation by dopaminergic and cholinergic agents.

The peripheral administration of the psychotomimetic drug phencyclidine (1-(phenylcyclohexyl) piperidine hydrochloride) (PCP) induces a dose-related ipsilateral rotation in unilateral substantia nigra electrolytically-lesioned rats. The intensity of this rotation can be modulated by administration of various dopaminergic and cholinergic agents. Injection of alpha-methylparatyrosine methylester (125 mg/kg) or haloperidol (1 mg/kg) inhibited the ipsilateral circling behavior. Pimozide (1 mg/kg) also inhibitied the rotation, but to a lesser extent. The injection of the anticholinergic agent trihexyphenidyl (5 mg/kg) potentiated, and the cholinomimetic drug arecoline (5 mg/kg), depressed the rotation induced by PCP (7.5 mg/kg), It is probable that PCP possesses significant dopaminergic and anticholinergic properties. The capacity of PCP to induce rotation in this model may be related to its effects on dopaminergic and cholingergic neurons in the rat striatum. Thus, PCP may induce rotational behavior by potentiating dopaminergic transmission, by blocking cholinergic activity, or both; both of these effects have been demonstrated to be important in the generation of circling behavior in rats with nigrostriatal lesions.

Animals↗

PubMed1979

Ketamine-induced rotation: interaction with GABA-transaminase inhibitors and picrotoxin.

Ketamine in a dose of 100 mg/kg (IP) produced stereotypic behavior and vigorous rotation in adult male Sprague-Dawley rats. The first rotation phase, accompanied by head swinging, was short and terminated by the anesthetic phase which lasted 20-30 min. The second rotation phase began 1-3 min after the end of the anesthetic phase. A single dose of GABA-T inhibitors, gamma-vinyl GABA (1200 mg/kg, IP) or gamma-acetylenic GABA (100 mg/kg, IP) administered 4 hours prior to ketamine, shortened the first rotation phase, increased the anesthetic phase, changed the pattern of postanesthetic rotation and reduced total and net rotation scores. Picrotoxin (3 mg/kg) given 10 min prior to ketamine tended to act in the opposite direction although none of its effects reached statistical significance.

4-Aminobutyrate Transaminase↗

PubMed1992

Enhancement of rotational behavior induced by repeated administration of SKF38393 in rats with unilateral nigrostriatal 6-OHDA lesions.

To clarify if the enhancement of rotational behavior induced by repeated administration of SKF38393 is mediated by upregulation of D1 and/or D2 receptors in the striatum, we investigated effects of SCH23390 and sulpiride on SKF38393-induced rotational behavior and the changes in striatal dopamine receptors in rats with unilateral nigrostriatal 6-hydroxydopamine lesions (1). Repeated weekly administration of SKF38393 markedly enhanced the number of rotations and shortened the latency of rotational behavior depending on the number of SKF38393 administrations 1 or 6 weeks after the treatment with 6-OHDA (2). A selective D1 antagonist, SCH23390, but not a selective D2 antagonist, sulpiride, suppressed SKF38393-induced rotation and inhibited the enhancement by the repeated administration (3). Repeated administration of SKF38393 did not modify the density and the affinity of either the striatal D1 or D2 receptors in the striatum. These results suggest that the enhancement of SKF38393-induced rotational behavior by the repeated administration is not associated with the upregulation of striatal D1 and D2 receptors.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗

PubMed1994

Rotation of photoreceptor clusters in the developing Drosophila eye requires the nemo gene.

The Drosophila eye consists of a reiterative hexagonal array of photoreceptor cell clusters, the ommatidia. During normal morphogenesis, the clusters in the dorsal or ventral halves of the disc rotate 90 degrees in opposite directions, forming mirror images across a dorsoventral equator. In the mutant nemo (nmo), there is an initial turning of approximately 45 degrees, but further rotation is blocked. Genetic mosaic analysis indicates that the nmo gene acts upon each cluster as a whole; normal nmo function in one or more photoreceptor cells appears to be sufficient to induce full rotation. The nmo gene sequence encodes a serine/threonine protein kinase homolog, suggesting that the kinase is required to initiate the second step of rotation. In another mutant, roulette, excessive rotation through varying angles occurs in many ommatidia. This defect is suppressed by nmo, indicating that nmo acts upstream in a rotation-regulating pathway.

Amino Acid Sequence↗

PubMedDate not supplied

Differential inhibitory effects of MIF-1, Tyr-MIF-1, naloxone and beta-funaltrexamine on body rotation-induced analgesia in the meadow vole, Microtus pennsylvanicus.

The effects of body rotation in a horizontal plane and various opiate antagonists on the nociceptive responses of a day-active microtine rodent, the meadow vole, Microtus pennsylvanicus, were examined. Intermittent rotation (70 rpm, schedule of 30 sec on, 30 sec off) for 30 min induced significant analgesic responses in the voles for 15 min after rotation. These increases in thermal response latency were blocked by intraperitoneal pretreatment with either naloxone or the irreversible mu opiate receptor antagonist beta-funaltrexamine (beta-FNA; 10 mg/kg; 24 hr pretreatment). This antagonistic effect of beta-FNA indicates mu opioid involvement in the mediation of rotation-induced analgesia. The antiopiate peptides MIF-1 (Pro-Leu-Gly-NH2) and Tyr-MIF-1 also significantly reduced, though did not completely block, body rotation-induced opiate analgesia. This suggests that Tyr-MIF-1 and MIF-1 have significant antagonistic effects on mu opioid systems that are involved in the mediation of stress (rotation)-induced analgesia.

Analgesia↗

PubMed1996

An in vivo study of the primary and coupled rotations of the thoracic spine.

OBJECTIVE: To provide preliminary data on three-dimensional thoracic spine kinematics measured in vivo. DESIGN: This study measured the three planes of thoracic spine motion in normal subjects using an external measuring device. BACKGROUND: Few studies have investigated the primary and associated coupled rotations in the thoracic spine in vivo. Most knowledge of motion characteristics comes from in vitro studies which have limitations. There is a lack of agreement on the patterns of thoracic coupled motion especially that between lateral flexion and axial rotation. METHODS: Thoracic motion was examined in 60 normal subjects (30 males, 30 females) aged 18-24 years. The primary and coupled rotations of the thoracic regions T(1-4), T(4-8), T(8-12) were measured using a 3 SPACE Fastrak system. RESULTS: The three thoracic regions displayed the characteristic variations in range and distribution of primary rotations previously described. The pattern of coupled motion varied between subjects but an ipsilateral pattern predominated between lateral flexion and axial rotation in the middle and lower thoracic regions while the upper thoracic region was found to exhibit either a contralateral or ipsilateral pattern. Gender did not influence results. CONCLUSIONS: The pattern of coupled motion in the thoracic spine demonstrated some variability between subjects in vivo. Lateral flexion and axial rotation were strongly coupled with overall, their relationship being predominantly ipsilateral.

Journal Article↗

PubMedDate not supplied

Sex differences in amphetamine-elicited rotational behavior and the lateralization of striatal dopamine in rats.

Sex differences are described in both a lateralized behavior (amphetamine-elicited rotation) and in the lateralization of striatal dopamine (DA) content. Amphetamine (AMPH) elicited significantly more partial turns, total rotations and lateralized (net) rotations in female, than in male rats. The two sexes also differed in their pattern of net rotations over time. In females, but not males, the striatum containing higher DA levels after amphetamine was consistently found to be contralateral to the dominant direction of rotation observed in the first 5 min interval after AMPH. No relationship was found between rotational behavior and medial frontal cortex DA or norepinephrine. The results are discussed in reference to cerebral lateralization in humans, and to possible sex differences in the modulatory effects of gonadal steroid hormones on striatal function.

Animals↗

PubMed1995

Evolution of coronary artery pattern according to short-axis aortopulmonary rotation: a new categorization for complete transposition of the great arteries.

OBJECTIVES: We studied the correlation between coronary artery pattern and aortopulmonary rotation in complete transposition of the great arteries. BACKGROUND: Classifications of the coronary arteries in complete transposition are puzzling and incomplete. METHODS: Coronary artery anatomy and relation of the great arteries were identified at angiography, echocardiography, surgical intervention or autopsy in 76 patients with complete transposition from 1988 to 1993. Five main types (type 0 and Shaher types 1,2,4 and 9) and their similar variants of epicardial configuration were categorized into five patterns (O, I, II, IV and IX). In addition, data from 568 cases from published reports were collected for analysis. RESULTS: As the aorta rotated from a left anterior to a directly anterior location relative to the pulmonary trunk, the left anterior descending coronary artery arose from the left-hand sinus together with the right coronary artery (type 0, one case decreased to no cases); then it gradually shifted to the left to have the same origin as the left circumflex coronary artery from the right-hand sinus (type 1, 10 cases increased to 146, p < 0.0003). When the aorta rotated farther clockwise from directly anterior to right anterior (type 1, 146 cases increased to 235; type 2, 9 cases increased to 50, p < 0.0006) or from right anterior to right lateral (type 1, 235 cases decreased to 6 cases; type 2, 50 cases decreased to 20, p < 0.00000), the left circumflex coronary artery tended to move retropulmonically and originated from the left-hand sinus with the right coronary artery (type 2). When the aorta moved from right anterior to right lateral (type 2, 50 cases decreased to 20; type 4, 13 cases increased to 14, p < 0.031) or from right lateral to right posterior (type 2, 20 cases decreased to 1; type 4, 14 cases increased to 16, p < 0.0003), the right coronary artery shifted to the right-hand sinus anteaortically to join the left anterior descending coronary artery (type 4). Finally, the left anterior descending coronary artery combined with the left circumflex coronary artery (type 9, 12 cases increased to 21, p = 0.407) to become the usual pattern for normally related great arteries. Eta-square analysis showed that the evolution from pattern O to IX was dependent on clockwise aortopulmonary rotation. CONCLUSIONS: The coronary arteries in complete transposition of the great arteries can be classified into five patterns and their evolution deduced on the basis of aortopulmonary rotation. Dependence of coronary artery type on aortopulmonary rotation made it possible to anticipate the coronary pattern from the relation of the great arteries in transposition.

Adolescent↗

PubMed2006

Can stock rotation effectively mitigate EMS medication exposure to excessive heat and cold?

The United States Pharmacopeia recently published a general chapter specifically addressing on-ambulance storage of medications, including a suggestion for stock rotation. This study describes the effectiveness of a simple stock rotation strategy in mitigating EMS medication exposure to excessive heat and cold. Previously collected on-ambulance temperature data from 5 US cities were randomly resampled to generate model exposures of 2 days to 6 months duration. The temperature measurements for every other 24-hour period were then set at 20 degrees C to model the rotation of medications into a controlled environment. For each model, we then determined consistency with the official United States Pharmacopeia definition of controlled room temperature. Without stock rotation, excessive heat occurred in 39.9% of the model exposures. With stock rotation, exposures to excessive heat occurred in less than 1% of northern city models and in 2.9% of the central US models. Stock rotation did not reduce heat exposures in the models for southern cities.

Ambulances↗

PubMed2006

Moment arms of forearm rotators.

BACKGROUND: Rotation about a longitudinal axis of the forearm has been a matter of investigation for over 100 years. However, most studies were limited to only a few muscles and to their action in specific set positions of elbow and forearm rotation. This investigation aims at determining the moment arms of muscles that contribute to pronation and supination at three different angles of elbow flexion throughout the entire range of forearm rotation. METHODS: Muscle moment arms were derived from tendon excursions that were recorded on a full-size epoxy model of the radioulnar complex. The results were verified on a fresh cadaver specimen. FINDINGS: Moment arms of all major supinators exhibit peak values in 40-50 degrees of pronation, for all three positions of the elbow. These peak values vary with elbow position, the biceps muscle showing the highest dependency with its greatest moment arm in 90 degrees of elbow flexion. The pronators show a maximum of moment arm about the neutral position, with little dependency on elbow flexion. Brachioradialis brings the pronated, or supinated forearm into the neutral position. The bow of the radius is in function comparable to the 'throw' of a crankshaft, forming a greater lever arm between the point of insertion of the muscles and the axis of rotation of the radius. INTERPRETATION: The observations drawn from this study could be of eminent value in planning rotator muscle transplantation, in understanding functional disorders after injury, and in the physical treatment of forearm rotator muscle deficiency. Reconstruction of the physiological anatomical arrangement in the treatment of injuries is strongly recommended for restoration of function.

Cadaver↗

PubMed2006

Amphetamine induced rotation in the assessment of lesions and grafts in the unilateral rat model of Parkinson's disease.

In the unilateral rat model of Parkinson's disease (PD), amphetamine induced rotation is widely used as an index of both lesion deficits and of graft-derived recovery. We have analysed the time course of the rotational response in lesioned rats, and in rats with lesions and dopamine grafts. In lesioned rats, the rotation exhibited a typical dose-dependent response, with low rates of rotation in the first 10 min after injection, rising gradually to a maximum after 20-30 min. Grafted rats exhibited a peak of rotation in the first 10 min after injection, which then fell to a minimum after 30 min. We demonstrate that the response seen in grafted rats is both drug and dose-dependent and show that the rotational profile results from interaction of the grafted and intact striata which exhibit differential temporal responses to the amphetamine.

Amphetamine↗

PubMed2004

Development and application of rotationally compensated RARE.

In this paper we describe a new extension to the RARE rapid imaging technique--ROTACOR--which compensates for constant sample rotational motion by rotating the direction of the gradient coordinate system (read and phase directions) between each refocusing RF pulse and therefore between each acquisition of a line of k-space in the read direction. In the laboratory frame this corresponds to an irregularly sampled k-space raster; for a sample rotating at the predefined rotation rate this will correspond to the sampling of a rectilinear k-space raster. This technique is applied to two rotating systems. First, to demonstrate the technique, a rotating mixing paddle in water is imaged using conventional RARE and then using the ROTACOR sequence, demonstrating the improvement of image quality produced by ROTACOR. Second, ROTACOR is used to image the deformation of water droplets in silicone oil, being sheared in a wide-gap Couette cell. Accurate imaging of the droplet shape as a function of shear rate, permits determination of the interfacial tension between the two fluids concerned; the results compare favourably with reported literature values.

Journal Article↗

PubMed2005

Comparison of the effects of nicotine and epibatidine given in combination with nomifensine on rotational behaviour in rats.

We studied the effects of nicotine and epibatidine on rotational behaviour in 6-hydroxydopamine-lesioned rats. The nicotinic agonists were given acutely and repeatedly either alone or in combination with a dopamine uptake inhibitor, nomifensine. Neither nicotine nor epibatidine alone produced acutely ipsilateral rotational behaviour in rats. However, when given repeatedly once a day for five days, nicotine (0.5 mg/kg) and epibatidine (0.6 microg/kg but not 3.0 microg/kg) induced ipsilateral rotations indicating sensitization of the nigrostriatal dopaminergic system to activation by repeated treatment with nicotinic agonists. Nomifensine (3 mg/kg) alone induced acutely ipsilateral rotations and the effect was enhanced after repeated administration of nomifensine. When the combination of nomifensine and nicotinic agonists was given acutely, the rotational effect of nomifensine was enhanced by nicotine (0.5 mg/kg) but not by either dose of epibatidine. When given repeatedly, nicotine and epibatidine 0.6 microg/kg tended to prolong whereas epibatidine 3.0 microg/kg tended to inhibit the enhanced rotational response to repeated nomifensine. The sensitization of the nigrostriatal dopaminergic pathway might be involved in the beneficial effects of nicotine in Parkinson's disease by allowing the remaining dopaminergic synapses to compensate for the functional deficiency of nigrostriatal pathway.

Adrenergic Agents↗

PubMed2005

A rotation-invariant spherical harmonic decomposition method for mapping intravoxel multiple fiber structures.

A new rotation-invariant spherical harmonic decomposition (SHD) method is proposed in this paper for analyzing high angular resolution diffusion (HARD) imaging. Regular SHD methods have been used to characterize the features of the apparent diffusion coefficient (ADC) profile measured by the HARD technique. However, these regular SHD methods are rotation-variant, i.e., the magnitude and/or the phase of the harmonic components changes with the rotation of the ADC profile. We propose a new rotation-invariant SHD (RI-SHD) method based on the rotation-invariant property of a diffusion tensor model. The basic idea of the proposed method is to reorient the measured ADC profile into a local coordinate system determined by the three eigenvectors of the diffusion tensor in each imaging voxel, and then apply a SHD to the ADC profile. Both simulations and in vivo experiments were carried out to validate the method. Comparisons were made between the component maps from a regular SHD method, diffusion circular spectrum mapping (DCSM) method and the proposed RI-SHD method. The results indicate that the regular SHD maps vary significantly with the rotation of the diffusion-encoding scheme, whereas the maps of the DCSM and the proposed method remain unchanged. In particular, the (0,0)-th, (2,2)-th and (4,4)-th component maps from the RI-SHD method exhibited good consistency with the 0th, 2nd and 4th order maps of the DCSM method, respectively. Compared with the regular SHD methods used in HARD imaging, the proposed RI-SHD method is superior in characterizing the diffusion patterns of multiple fiber structures between different brain regions or across subjects.

Adult↗

PubMed1999

The influence of spatial reference frames on imagined object- and viewer rotations.

The human visual system can represent an object's spatial structure with respect to multiple frames of reference. It can also utilize multiple reference frames to mentally transform such representations. Recent studies have shown that performance on some mental transformations is not equivalent: Imagined object rotations tend to be more difficult than imagined viewer rotations. We reviewed several related research domains to understand this discrepancy in terms of the different reference frames associated with each imagined movement. An examination of the mental rotation literature revealed that observers' difficulties in predicting an object's rotational outcome may stem from a general deficit with imagining the cohesive rotation of the object's intrinsic frame. Such judgments are thus more reliant on supplementary information provided by other frames, such as the environmental frame. In contrast, as assessed in motor imagery and other studies, imagined rotations of the viewer's relative frame are performed cohesively and are thus mostly immune to effects of other frames.

Attention↗

PubMed1977

Intracellular rotation and the phototropic response of Phycomyces.

Experimental evidence indicates that during phototropism, Phycomyces sporangiophores use their own net rotation to convert an apparently spatial stimulus to a temporal one. Conversion to a continuous temporal stimulus insures that phototropism never adapts as long as the spatial asymmetry in illumination is maintained. If this temporal stimulus is circumvented by rotating the cell backwards so that there is no net rotation of some of the receptors relative to the light, the response can be reduced by two-thirds. The system thus adapts to the incident light, resulting in a reduced response. For the illumination of a transparent cell, this compensating rotation speed is 10 degrees/min counterclockwise and probably corresponds to the photoreceptor rotation in the most effective part of the growing zone. We infer that this region is in the upper portion of the growing zone and that the receptor system rotates integrally with that region of the cell.

Adaptation, Physiological↗