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PubMed2005

Longitudinal cooling of non-neutral plasma by energy exchange.

The optimal values of Q and Deltaomega (Deltaomega identical withomega-Omega) for cooling a pure electron plasma with a microwave bath have been calculated. An electron plasma, which has no internal degree of freedom, cannot be cooled below the temperature of a heat bath. However, longitudinal cooling can be achieved by energy transfer from the poorly cooled longitudinal degree of freedom to the well-cooled (by synchrotron radiation) transverse degree of freedom. To do this, a microwave bath is introduced to the electron plasma. A microwave tuned to a frequency below the gyrofrequency forces electrons moving towards the microwave to absorb a microwave photon. The electrons move up one in Landau state and then lose their longitudinal momenta. In this process, the longitudinal temperature of the electron plasma decreases. On the basis that the perpendicular temperature is below the Landau temperature of the plasma, we set up two level transition equations and then derive a Fokker-Planck equation from them. With the aid of a finite element method (FEM) code for the equation, the cooling times for several values of the magnetic field, the microwave cavity (Q), and the relative detuning frequency from the gyrofrequency (Deltaomega) are calculated. Thus optimal values of the microwave cavity and the detuning frequency for longitudinal cooling of a strongly magnetized electron plasma with a microwave bath have been found. By applying these optimal values with an appropriate microwave intensity, the best cooling can be obtained. For an electron plasma magnetized to 10 T, the cooling time to the solid state is approximately two hours.

Journal Article↗
PubMed2005

Scaling of longitudinal and transverse velocity increments in a cylinder wake.

Longitudinal and transverse velocity increments are measured both temporally and spatially using two X-wire probes in the intermediate region of a cylinder wake over Taylor microscale Reynolds numbers in the range of 100-300. The scaling exponents of both the spatial and temporal longitudinal velocity increments agree favorably with the predictions of Kolmogorov and She and Leveque. The scaling exponents of the transverse velocity increments are considerably smaller than those of the longitudinal ones, with the values for spatial transverse velocity increments being slightly larger than the temporal ones. The difference between the scaling exponents of the longitudinal and transverse velocity increments is examined against the refined similarity hypotheses for transverse velocity increments (RSHT) proposed by Chen It is found that the RSHT can account for the difference between the scaling exponents of the longitudinal and spatial transverse velocity increments at all Reynolds numbers considered.

Journal Article↗
PubMed1999

Longitudinal sampling and aliasing in spiral CT.

Although analyses of in-plane aliasing have been done for conventional computed tomography (CT) images, longitudinal aliasing in spiral CT has not been properly investigated. We propose a mathematical model of the three-dimensional (3-D) sampling scheme in spiral CT and analyze its effects on longitudinal aliasing. We investigated longitudinal aliasing as a function of the helical-interpolation algorithm, pitch, and reconstruction interval using CT simulations and actual phantom scans. Our model predicts, and we verified, that for a radially uniform object at the isocenter, the spiral sampling scheme results in spatially varying cancellation of the aliased spectral islands which, in turn, results in spatially varying longitudinal aliasing. The aliasing is minimal at the scanner isocenter, but worsens with distance from it and rapidly becomes significant. Our results agree with published results observed at the isocenter of the scanner and further provide new insight into the aliasing conditions at off-isocenter locations with respect to the pitch, interpolation algorithm, and reconstruction interval. We conclude that longitudinal aliasing at off-isocenter locations can be significant, and that its magnitude and effects cannot be predicted by measurements made only at the scanner isocenter.

Algorithms↗
PubMed1985

Uterine contractility and actions of catecholamines in longitudinal and circular uterine layers from ovariectomised guinea-pigs: the effects of ovarian steroids.

The influence of ovarian steroids upon responses to electrical stimulation and to activation of adrenoreceptors in field-stimulated preparations of longitudinal and circular myometrium from ovariectomised guinea-pigs has been investigated. Adult virgin guinea-pigs were bilaterally ovariectomised and were treated two weeks later with thrice-weekly injections of oestradiol cypionate for two weeks, or treated as in then given oestradiol cypionate and progesterone for a further four days. Control groups of bilaterally ovariectomised and sham ovariectomised animals remained untreated. Both myometrial layers from untreated ovariectomised guinea-pigs were atrophied. Responses to field stimulation in the circular myometrium were much smaller than those in the longitudinal layer. Steroid pretreatment, most notably treatment with oestradiol and progesterone, were associated with decreased and increased responsiveness to electrical stimulation in the circular and longitudinal myometrial layers respectively. Adrenaline and noradrenaline were consistently excitatory on preparations of circular myometrium from ovariectomised animals. Responses comprised either enhancement of electrically-evoked contractions, or, with the higher concentrations, the appearance of rapid contractions superimposed upon an increase in basal tone. The latter effects were also evident in preparations of circular myometrium from sham operated animals. In preparations of longitudinal myometrium from untreated ovariectomised animals noradrenaline consistently and adrenaline usually caused a simple enhancement of the magnitude of the evoked contractions. Phentolamine reduced the excitatory effects of both amines in both layers. In circular myometrium from the oestrogen-treated group both catecholamines produced phentolamine-sensitive enhancement of electrically-evoked contractions, but did not cause high frequency contractions or increased tonus. Noradrenaline and adrenaline produced qualitatively similar phentolamine-sensitive effects in preparations of longitudinal myometrium from this group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1970

The Schultz-Dale response of the longitudinal muscle strip preparation of guinea-pig ileum.

1. The mast-cell distribution in the various layers of the ileum has been described.2. Histamine-content, anaphylactic histamine-release and the anaphylactic dose-response curve of the full-thickness ileum and of the longitudinal muscle strip have been measured and compared.3. Tetrodotoxin 10(-7) g/ml had no obvious effect on the anaphylactic dose-response curve of either preparation. This suggests that the plexus is not of any great importance in the Schultz-Dale reaction.4. Exposure of the longitudinal muscle strip to octylamine 10(-3) g/ml for 1 min reduced the mast cell content by 95-100%. After this treatment the dose-response curve to antigen was eliminated, although the muscle still responded to small doses of histamine and to anaphylactic mediators. Pretreatment of antibody with octylamine did not impair passive sensitization and subsequent response to antigenic challenge. This suggests that the classical Schultz-Dale reaction in the strip is mediated mainly by mast cells, and possibly other cells, and is probably not due to a direct effect of the antigen-antibody reaction on the smooth muscle.5. The typical three-phase anaphylactic response (quick contraction, quick relaxation, slow contraction) of full-thickness ileum is discussed and compared with the predominantly two-phase response of the longitudinal muscle strip. No evidence was found for the release of a relaxation-factor. It is suggested that the initial fast phase may be due to mediators released from mast cells among the longitudinal muscle fibres, and the sustained contraction to a second wave of mediators reaching the longitudinal muscle from deeper layers of the ileum.

Amines↗
PubMed1983

Actions of neurotransmitters and peptides on longitudinal and circular muscle of the rat portal vein.

The reactivity of longitudinal and circular muscle of the rat portal vein to noradrenaline, acetylcholine, 5-hydroxytryptamine, substance P, angiotensin II and neurotensin was compared. Longitudinal muscle was prepared as longitudinal strips and circular muscle was studied as transversally cut rings. Longitudinal muscle was more sensitive than circular muscle to acetylcholine, 5-hydroxytryptamine and angiotensin II, whereas both muscle layers were equally sensitive to noradrenaline and substance P. Circular muscle was generally unresponsive to neurotensin. Differential sensitivity of longitudinal and circular muscle layers suggests that these two muscle layers do not necessarily operate in unison.

Acetylcholine↗
PubMed2003

Arterial wall adaptation under elevated longitudinal stretch in organ culture.

Arteries in vivo are subjected to large longitudinal stretch which may change significantly due to vascular disease and surgery. However, little is known about the effect of longitudinal stretch on vascular function and wall remodeling, although the effects of tensile and shear stress from blood pressure and flow have been well documented. To study the effect of longitudinal stretch on vascular function and wall remodeling, porcine carotid arteries were longitudinally stretched 20% more than in vivo for 5 days while being maintained in an ex vivo organ culture system under conditions of pulsatile flow at physiologic pressure. Vessel viability was demonstrated by strong vasomotor responses to norepinephrine (NE, 10(-6) M), carbachol (10(-6) M), and sodium nitroprusside (10(-5) M), as well as by dense staining for mitochondrial activity and a low occurrence of cell necrosis. Cell proliferation was examined by incorporation of bromodeoxyuridine (BrdU). Results showed that arteries maintain normal structure and viability after 5 days in organ culture. Both the stretched and control arteries demonstrated significant contractile responses. For example, both stretched and control arteries showed approximately 10% diameter contraction in response to NE. Stretched arteries contained 8% BrdU-positive cells compared to 5% in controls (p<0.05). These results indicate that longitudinal stretch promotes cell proliferation in arteries while maintaining arterial function.

Adaptation, Physiological↗
PubMedDate not supplied

The effect of strong longitudinal magnetic fields on dose deposition from electron and photon beams.

The use of strong, uniform, longitudinal magnetic fields for external electron and photon beam irradiation is considered. Using the EGS4 Monte Carlo code modified to account for the presence of magnetic fields, dramatic narrowing of penumbra for photon and electron irradiations is demonstrated. In the vicinity of heterogeneities, "hot" and "cold" spots due to multiple scattering in electron beams are reduced substantially. However, in the presence of strong magnetic fields, the effect of inhomogeneities can be observed far from the location of the inhomogeneity due to reduced "washout" caused by lateral multiple scattering. The enhanced "Bragg peak," proposed or calculated by other authors, is not observed on the central axis of broad beams, owing to lateral equilibrium. It is proven that for broad parallel beams, the central axis depth-dose curve is independent of the strength of the external longitudinal magnetic field, as long as it is uniform. However, strong longitudinal magnetic fields can induce enhancements by redirection of the electron fields coming from point sources. Strong uniform longitudinal magnetic fields provide a way of controlling the spreading of electron beams due to multiple scattering, making the electron beams more "geometrical" in character, simplifying dose-deposition patterns, possibly allowing electron beams to be used in new ways for radiotherapy. Photon therapy also benefits from strong uniform longitudinal magnetic fields since the penumbra or other lateral disequilibrium effects associated with lateral electron transport can be eliminated.

Biophysical Phenomena↗
PubMed2005

Initial effects of anti-pronation tape on the medial longitudinal arch during walking and running.

OBJECTIVES: To investigate the effect of an augmented LowDye taping technique on the medial longitudinal arch of the foot during dynamic tasks such as walking and jogging, and to elucidate the relation between tape induced changes in static and dynamic foot posture. METHODS: Seventeen subjects (mean (SD) age 27 (5.8) years) who were asymptomatic and exhibited a navicular drop greater than 10 mm were studied. Medial longitudinal arch height standardised to foot length during standing and at mid-stance of walking and jogging was measured from digital video images taken before and after the application of an anti-pronation taping technique. A no tape control condition was also included. RESULTS: Compared with the no tape control condition, tape produced a significant mean (SD) increase in the medial longitudinal arch height index of 0.031 (0.015), 0.026 (0.014), and 0.016 (0.017) during standing, walking, and jogging respectively (p < 0.05). The relative increase in medial longitudinal arch height represents an anti-pronation effect. The tape induced changes in the medial longitudinal arch height measured during standing correlated strongly with those measured during walking and jogging (Pearson's r = 0.7 and 0.76 respectively). CONCLUSIONS: The augmented LowDye tape was effective in controlling pronation during both static and dynamic activity. Tape induced changes in static foot posture paralleled those during walking and jogging.

Adult↗
PubMed1989

Characterization of the effects of AHN 086, an irreversible ligand of "peripheral" benzodiazepine receptors, on contraction in guinea-pig atrial and ileal longitudinal smooth muscle.

The effects of AHN 086 and its reversibly acting structural analogue Ro 5-4864 were studied in the spontaneously beating guinea-pig atria and field-stimulated guinea-pig ileal longitudinal smooth muscle in the presence and absence of dihydropyridine calcium channel modulators. The treatment of guinea-pig atria with AHN 086 followed by extensive washing did not alter contraction. However, AHN 086 (0.5 microM) potentiated (88%) the positive inotropic responses by BAY K 8644, an effect that was not reversed by extensive washing of the tissue. Higher concentrations of AHN 086 (greater than 2 microM) irreversibly inhibited the intropic, but not the chronotropic responses to BAY K 8644, nifedipine, and isoproterenol. Ro 5-4864 (10 microM) produced a reversible enhancement of the inotropic responses and block of the chronotropic responses to BAY K 8644. In guinea-pig ileal longitudinal smooth muscle, both AHN 086 and Ro 5-4864 reversibly inhibited field-stimulated contractions. Neither Ro 5-4864 nor AHN 086 affected the ability of nifedipine to inhibit field-stimulated contractions of ileal longitudinal smooth muscle. Treatment of intact atrial with 5 microM AHN 086 followed by extensive washing resulted in a significant inhibition (30-50%) of [3H]Ro 5-4864 binding to peripheral benzodiazepine receptors and of [3H]nitrendipine binding to voltage-operated calcium channels, but did not affect [3H]dihydroalprenolol binding to beta-adrenergic receptors on atrial membranes. The same treatment applied to intact ileal longitudinal smooth muscle affected neither [3H] (-)-quinuclidinyl benzilate binding to muscarine receptors nor [3H]nitrendipine binding, but did result in a significant inhibition (30-50%) of [3H]Ro 5-4864 binding to ileal longitudinal smooth muscle membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1981

Dominance of longitudinal muscle in propagation of intestinal slow waves.

The purpose of these experiments was to test the hypothesis that circular muscle plays an active role in the propagation of intestinal slow waves, specifically be providing excitatory current through a process of regenerative amplification. With volume-recording techniques and microelectrode recordings we obtained the following results that are not consistent with such a mechanism: 1) slow waves propagated without delay or decrease in amplitude along segments of cat jejunum devoid of a ring of circular muscle up to 3 mm wide, i.e., across a longitudinal muscle bridge more than 4 space constants long (9 of 11 preparations) but did not propagate across a circumferential cut through the longitudinal muscle layer (14 of 14 preparations); 2) the membrane current associated with the slow wave had a pronounced inward component when recorded from either the serosal or the mucosal side of the longitudinal muscle bridge but was entirely outward when recorded from either the mucosal or the serosal side of exposed circular muscle, including those preparations in which various thicknesses of circular muscle were removed from the mucosal side of the recording area; 3) slow-wave amplitudes recorded intracellularly from intact (n = 9) and isolated (n = 8) longitudinal muscle preparations were not significantly different (27.0 +/- 4.3 vs. 25.4 +/- 5.3 (SD) mV); 4) after 30 min in 4.4 X 10(-6) M verapamil, slow-wave amplitude did not significantly decrease, although contractile activity had long since terminated. These results are more consistent with the hypothesis that longitudinal muscle provides most, if not all, of the current required for slow-wave propagation in the small intestine.

Action Potentials↗
PubMed1983

Sites of action of testosterone and estradiol on longitudinal bone growth.

In this study the mechanisms by which sex steroids influence body growth were investigated. The effect of different doses of testosterone propionate on longitudinal bone growth and body weight gain was studied in a) gonadectomized male rats, b) gonadohypophysectomized male rats, and c) gonadohypophysectomized male rats given replacement therapy with bovine growth hormone (bGH). The effect of different doses of estradiol benzoate on the same growth parameters was studied in female rats divided into the same experimental groups as the males. Accumulated longitudinal bone growth was determined using oxytetracycline as an intravital marker. Testosterone caused a dose-dependent increase in longitudinal bone growth in gonadectomized male rats. In contrast, testosterone exerted no significant increase in longitudinal bone growth in gonadohypophysectomized male rats with and without bGH replacement therapy. Treatment with estrogen inhibited longitudinal bone growth and body weight gain. The inhibitory effect of estradiol was approximately the same in gonadohypophysectomized female rats given bGH replacement therapy as in gonadectomized female rats. The results suggest that testosterone exerts its stimulatory effect on body growth mainly by modulating hypothalamopituitary functions, e.g., by altering the secretory pattern of GH. On the other hand, it seems that changes in the hypothalamopituitary functions are less significant for the inhibitory effect of estradiol on body growth. It is concluded from this study that the sites of action for estrogen and testosterone in modulating body growth in the rat are different.

Aging↗
PubMed1995

Agonist-mediated activation of PLA2 initiates Ca2+ mobilization in intestinal longitudinal smooth muscle.

Recent studies have shown that Ca2+ mobilization in longitudinal muscle is initiated by inositol 1,4,5-trisphosphate (IP3)-independent Ca2+ influx that acts as a trigger for Ca(2+)-induced Ca2R release. The present study examined whether arachidonic acid (AA) acts as mediator of the initial Ca2+ influx. Cholecystokinin octapeptide caused transient concentration-dependent increase in AA release in dispersed intestinal longitudinal but not circular muscle cells followed by sustained increase in both muscle cell types. The initial increase in AA release coincided with the initial Ca2+ transient and muscle contraction: all three events were abolished by guanosine 5'-O-(2-thiodiphosphate), pertussis toxin (PTX), and the phospholipase A2 (PLA2) inhibitor, dimethyleicosadienoic acid, but were not affected by calphostin C or neomycin. Exogenous AA caused concentration-dependent contraction and increase in cytosolic free Ca2+ ([Ca2+]i) in longitudinal but not circular muscle cells; both events were abolished by Ca2+ channel blockers. Depletion of Ca2+ stores with thapsigargin attenuated with thapsigargin attenuated agonist- and AA-mediated increase in [Ca2+]i and contraction in longitudinal muscle cells: the residual [Ca2+]i increase (35%) and contraction (25%) reflected the component of Ca2+ influx. We conclude that AA released by agonist-mediated G protein-dependent PTX-sensitive activation of PLA2 mediates Ca2+ influx, which then triggers Ca(2+)-induced Ca2+ release. The process is independent of phosphatidylinositol hydrolysis and occurs exclusively in longitudinal smooth muscle, in which Ca2+ release channels are highly sensitive to Ca2+, ryanodine, and cyclic ADP-ribose and insensitive to IP3.

Animals↗
PubMed1984

"Functional polarity" of the spinal cord caused by its longitudinal electric dipole moment.

Specific reactions of the vertebrates that occur through lengthwise application of direct-current (DC) electric fields in the spinal cord and are dependent on the direction of the current (e.g., electric narcosis and electric excitation) can be explained by the existence of a longitudinal dipole moment in the spinal cord. The relationship between "functional polarity of the spinal cord" and its longitudinal dipole moment was established in two different experimental series. 1) Reactions of functional polarity were quantitatively tested on Amphioxus (lancelet) and on numerous Teleostei. On this point the findings of other researchers were confirmed and complemented. 2) Fresh, almost-live spinal cord preparations (cow) were quantitatively tested using pyroelectric (PE) methods. A longitudinal electric dipole moment was demonstrated along the entire length of the white matter. Moreover fresh spinal cord preparations showed a polar orientation on sudden temperature change in a high-voltage DC field. The PE behavior showed a pronounced electric field dependence. Because the white matter is largely composed of longitudinally arranged nerve fibers, individual axons may also have a longitudinal electric dipole moment. Consequently one might expect the following: polar orientation of the growing neurite by an applied DC field, an electric dipole field inside and outside the axon, and a transport of charge carriers along the lines of flux of this dipole field. Moreover PE and piezoelectric (PZE) properties of the neuron should be provable.

Animals↗
PubMed2003

Evidence for longitudinal and transverse fiber conduction in human pulmonary veins: relevance for catheter ablation.

BACKGROUND: Segmental ostial ablation of the pulmonary veins (PVs) allows for successful control of paroxysmal atrial fibrillation in many patients. We hypothesized that mapping of the left atrial-PV junction with a 64-electrode basket catheter would allow characterization of conduction patterns that would identify sites where ablation is required to electrically isolate the PV. METHODS AND RESULTS: A 64-electrode basket catheter was used to map the PVs of 50 patients undergoing PV isolation procedures for the treatment of atrial fibrillation. Activation along each spline was classified as reflecting either longitudinal, transverse, or no activation. A longitudinal activation pattern recorded along a spline during sinus rhythm in right-sided PV and during CS pacing in left-sided PV before the delivery of any RF energy application had a sensitivity and specificity for a required ostial ablation site of 83% and 82%, respectively. When longitudinal activation along the spline was present during preablation recordings in both sinus rhythm and CS pacing, the sensitivity and specificity were 92% and 90%, respectively. A longitudinal activation pattern after the first RF application that produced a change in PV activation sequence had a sensitivity and specificity for sites where further ablation was required of 91% and 94%, respectively. CONCLUSIONS: Mapping of PV activation with a 64-electrode basket catheter allows characterization of conduction patterns that predict requirement for ablation. The presence of a longitudinal activation pattern is a strong predictor of ostial sites where ablative energy is required to electrically isolate the PV.

Atrial Fibrillation↗
PubMed1987

Effects of increasing intercellular resistance on transverse and longitudinal propagation in sheep epicardial muscle.

Propagation in cardiac muscle is faster in the longitudinal than in the transverse axis of the cells. Yet, as a result of the larger upstroke velocity of action potentials propagating transversely, it has been suggested that longitudinal propagation is more vulnerable to block. To study the relation between conduction velocity and maximal upstroke velocity (Vmax), as well as the time course of conduction delay and block in the transverse vs. longitudinal direction, thin square pieces of sheep epicardial muscle were superfused with the cellular uncoupler heptanol (1.5 mM). Action potentials were recorded with microelectrodes at opposite corners of the preparation while stimulating alternately in the longitudinal or transverse direction with bipolar electrodes located at contralateral corners. In all cases, block occurred more promptly for transverse than for longitudinal propagation. The decrease in conduction velocity was greater than expected for Vmax decay and, in some cases, Vmax increased while conduction velocity decreased. In the presence of high grade conduction impairment, foot potentials appeared and the upstrokes became "notched." We conclude that when intercellular coupling is impaired, transverse propagation is more vulnerable to block, and need not be dependent on changes in Vmax.

Action Potentials↗
PubMed1973

Transverse spread and longitudinal dissociation in the distal A-V conducting system.

Isolated preparations of portions of the canine intraventricular conducting system were studied by microelectrode techniques in order to determine the nature of transverse spread and longitudinal dissociation of impulses in bundle branches and false tendons. Driving stimuli were delivered to an eccentric location on normal conducting tissue, and the arrival times of the propagating impulses were mapped along the length and width of the bundle branch, or along the false tendon ipsilateral and contralateral to the site of stimulation. The difference between the arrival times on the two sides was found to decrease progressively as a function of distance from the site of stimulation, the data suggesting that transverse spread of impulses involves propagation through transverse crossover points between the longitudinally oriented conducting elements. Impulses originating eccentrically became uniformly conducted across the transverse axis of bundle branches 8-15 mm from the level of the stimulating electrode, and of false tendons 2-4 mm from the stimulus site. True longitudinal dissociation, producing conduction maps different from those representing normal transverse propagation, was seen occasionally in tissue having longitudinally oriented strips of abnormal tissue. However, early premature stimulation commonly resulted in longitudinal temporal dissociation of the premature responses, possibly due to functional block in the transverse crossover fibers.

Action Potentials↗
PubMed1995

Differential expression and regulation of connexin-43 and cell-cell coupling in myocytes from the circular and longitudinal layers of bovine myometrium.

The expression and localization of the gap junction protein connexin-43 (Cx-43) as well as functional coupling were studied in myocytes from the two layers of the bovine myometrium: the circular and the longitudinal layers. Intercellular communication (measured by Lucifer yellow dye transfer through gap junctions) was more intense in the circular than in the longitudinal layer of the bovine myometrium. The circular layer also exhibited a greater degree of punctuate immunofluorescence to Cx-43. Myocytes from the circular layer expressed more Cx-43 messenger RNA (mRNA; 2.38 +/- 0.46, Cx-43 over 18S RNA) than the longitudinal layer (1.46 +/- 0.48, Cx-43 over 18S RNA; P < 0.05). The modulation of Cx-43 expression by sex steroids in the two myometrial layers was tested using a pure steroidal antiestrogen, EM-139. In myocytes from the circular layer, the level of Cx-43 mRNA was decreased after treatment with 0.1 microM EM-139 (1.37 +/- 0.25, Cx-43 over 18S RNA) compared to that in untreated cells (2.38 +/- 0.46, Cx-43 over 18S RNA), representing a 40% inhibition. In parallel, cell-cell coupling and the amount of Cx-43 protein were also reduced after antiestrogen treatment. In contrast, treatment of cells from the longitudinal layer with the antiestrogen did not significantly affect the level of Cx-43 mRNA, protein, or cell-cell coupling. These data demonstrate that Cx-43 protein and mRNA are expressed and regulated differentially in myocytes from the circular and longitudinal layers of bovine myometrium. Furthermore, the circular myometrial layer may represent a preferential target for estrogen regulation of the biochemical and mechanical processes controlling contractility.

Animals↗