Diagnosis of gaucher's disease and niemann-pick disease with small samples of venous blood.

Enzymes which catalyze the hydrolysis of glucocerebroside and sphingomyelin have been demonstrated in preparations of washed human white blood cells. The level of activity of these respective enzymes is markedly decreased in leukocyte preparations obtained from patients with Gaucher's and Niemann-Pick diseases. Assay of these enzymes may be useful in the differential diagnosis of the sphingolipidoses.

Differential sensitivity of proximal and distal coronary arteries to a nitric oxide donor following reperfusion injury or inhibition of nitric oxide synthesis.

OBJECTIVE: The effect of the nitric oxide donor, SIN-1, in proximal and distal coronary arteries with normal endothelium was characterised before and after inhibition of NO synthesis with L-nitroarginine methyl ester (L-NAME). The effect of reperfusion injury in vivo in similar vessels on the response to SIN-1 was also assessed. METHODS: In vitro reactivity of preconstricted coronary arterial rings was studied in control dogs (group 1), and dogs in which the left circumflex coronary artery was subjected in vivo to four acute occlusions of 5 min duration, with three intervening reperfusion periods of 5 min and a final reperfusion period of 60 min (group 2). The effects of acetylcholine and SIN-1 on the tone of left circumflex and left anterior descending coronary vascular rings were examined before and after treatment with L-NAME. RESULTS: Proximal [1851 (SEM 82) microns] and distal [477(19) microns] vessels were studied. In control dogs (group 1) acetylcholine caused relaxation in proximal and distal coronary arteries (p > 0.05). No difference in responsiveness of left circumflex or left anterior descending coronary arteries was observed in the control group. In group 2 the response to acetylcholine was significantly (p < 0.05) attenuated in left circumflex coronary arteries exposed to ischaemia and reperfusion compared with left anterior descending control rings from the same heart. Proximal vessels in group 1 and group 2 showed greater sensitivity to the vasodilator effects of SIN-1 than distal vessels. Proximal left circumflex vessels exposed to ischaemia and reperfusion showed enhanced sensitivity to the relaxant effects of SIN-1 compared to control proximal vessels obtained from the same hearts. Reperfusion was not associated with any alteration in sensitivity of distal vessels to SIN-1. Similarly, inhibition of the synthesis of endothelium derived relaxing factor (EDRF) by L-NAME resulted in an enhanced response to SIN-1 in proximal vessels only. CONCLUSIONS: Endothelium dependent vasodilatation is attenuated by ischaemia and reperfusion in both proximal and distal coronary arteries of the size studied. The response to direct nitric oxide donation (bypassing vascular endothelial synthesis of EDRF) is inhibited by a basal endothelial process present in proximal coronary arteries only. This inhibition is abolished following reperfusion injury or inhibition of NO synthesis.

7-Nitroindazole impedes erythrocyte flow response to isovolemic hemodilution in the cerebral capillary circulation.

The role of nitric oxide (NO) in the mechanism of hemodilution-induced cerebral hyperemia is unclear. Based on findings in hypoxemia, the authors hypothesize that NO of neuronal origin contributes to an increase in velocity of erythrocytes in the cerebral microcirculation during anemia produced by isovolemic hemodilution. The change in erythrocyte velocity in cerebrocortical capillaries was assessed by intravital fluorescence video microscopy. A closed cranial window was implanted over the frontoparietal cortex of barbiturate-anesthetized, ventilated adult rats. Erythrocytes were labeled in vitro with fluorescein isothiocyanate and infused intravenously, and their velocity in subsurface capillaries was measured by frame-to-frame image tracking. Arterial blood was withdrawn in increments of 2 mL and replaced by serum albumin; arterial blood pressure was maintained at control level with an infusion of methoxamine. Erythrocyte velocity increased progressively, reaching 215% of baseline, as arterial hematocrit was reduced from 45% to 17%. Pretreatment of a separate group of rats with 7-nitroindazole (20 mg/kg intraperitoneally), a relatively selective inhibitor of neuronal NO synthase, abolished the increase in velocity at hematocrits greater than 20%, but the maximum velocity attained at the lowest hematocrit was similar to that in the control group. The results suggest that NO from neuronal source may contribute to the increase in capillary erythrocyte flow during moderate isovolemic hemodilution.

Distribution and co-localization of 5-hydroxytryptamine, thyrotropin-releasing hormone and substance P in the cat medulla.

This study demonstrates the co-existence of three neurochemicals in ventral medullary neurons of the cat utilizing fluorescence immunohistochemistry. Neurons containing 5-hydroxytryptamine, thyrotropin-releasing hormone and substance P were identified within the rostrocaudal extent of the medulla, specifically within the raphe pallidus and raphe magnus and in the reticular formation of the ventrolateral medulla in the nucleus paragigantocellularis lateralis. Within the raphe pallidus the majority of 5-hydroxytryptamine-containing neurons were co-localized with thyrotropin-releasing hormone and substance P. However, in the raphe magnus the majority of stained neurons contained 5-hydroxytryptamine and thyrotropin-releasing hormone but were devoid of substance P. In the ventrolateral medulla two major populations of neurons were identified rostral to the inferior olivary nuclei, one containing 5-hydroxytryptamine and thyrotropin-releasing hormone, while a more lateral group contained substance P alone. More caudally, at the level of the inferior olives, the majority of 5-hydroxytryptamine-containing cells also displayed immunoreactivity for thyrotropin-releasing hormone and substance P. A consistent finding in both the ventromedial and ventrolateral regions of the medulla was a population of 5-hydroxytryptamine-containing cells which did not stain for either thyrotropin-releasing hormone or substance P. The functional role of co-localized neurochemicals remains unknown but co-existence of neurotransmitter substances in medullary neurons may allow for specific and multiple actions in the spinal cord.

Antisense oligodeoxynucleotide to a delta-opioid receptor messenger RNA selectively blocks the antinociception induced by intracerebroventricularly administered delta-, but not mu-, epsilon- or kappa-opioid receptor agonists in the mouse.

An antisense oligodeoxynucleotide to delta-opioid receptor messenger RNA was utilized to block the expression of mouse delta-opioid receptors for antinociception. The antinociception was measured by the tail-flick test in male ICR mice. Pretreatment with delta-antisense oligodeoxynucleotide (163 pmol) given intracerebroventricularly twice a day for one to four days produced a time-dependent inhibition of the tail-flick response induced by intracerebroventricularly administered (D-Ala2)deltorphin II (12.8 nmol). The (D-Ala2)deltorphin II-induced antinociception was significantly attenuated after three to four days of the delta-antisense oligodeoxynucleotide treatment, remained attenuated for two days and gradually recovered to the control level in four to 10 days after cessation of the pretreatment with delta-antisense oligodeoxynucleotide. Pretreatment with delta-antisense oligodeoxynucleotide (163 pmol) twice a day for four days markedly attenuated the antinociception induced by intracerebroventricularly administered (D-Ala2)deltorphin II and, to a lesser extent, by D-Pen2-D-Pen5-enkephalin and morphine, but not by (D-Ala2-MePhe4-Gly(ol)5)enkephalin, beta-endorphin or U50,488H. Mismatched oligodeoxynucleotide (163 pmol) was ineffective against the antinociception induced by these opioids. Our results provide the evidence that the cloned delta-opioid receptor is related to the pharmacologically classified delta 2-opioid receptor, and the antinociception induced by (D-Ala2)deltorphin II and, at least in part, by D-Pen2-D-Pen5-enkephalin and morphine given intracerebroventricularly is mediated by the stimulation of delta 2-opioid receptors. However, delta 2-opioid receptors are not involved in the antinociception induced by beta-endorphin, (D-Ala2-MePhe4-Gly(ol)5)enkephalin or U50,488H given intracerebroventricularly.

The effect of pretreatment with a delta 2-opioid receptor antisense oligodeoxynucleotide on the recovery from acute antinociceptive tolerance to delta 2-opioid receptor agonist in the mouse spinal cord.

1. An intrathecal (i.t.) injection of a selective delta 2-opioid receptor agonist, [D-Ala2]deltorphin II, produced an acute antinociceptive tolerance to the antinociceptive effect of a subsequent i.t. challenge of [D-Ala2]deltorphin II. This acute tolerance lasted 3 to 9 h and completely subsided by 12 h. The experiments were designed to examine the effect of pretreatment with an antisense oligodeoxynucleotide to delta 2-opioid receptor mRNA (delta-AS oligo) on the recovery from tolerance to [D-Ala2]deltorphin II-induced antinociception in male ICR mice. 2. Pretreatment with delta-AS oligo (1.63 to 163 pmol, i.t.), but not mismatched oligo (MM oligo) (163 pmol), prevented the recovery from acute tolerance to [D-Ala2]deltorphin II-induced antinociception in a dose-dependent manner. However, treatment with delta-AS oligo (163 pmol) did not prevent the recovery from tolerance to either the mu-opioid receptor agonist [D-Ala2,NMePhe4,Gly(ol)5]enkephalin (DAMGO) or the kappa-opioid receptor agonist U50,488H, indicating subtype specificity in the mechanism by which delta-AS oligo inhibits recovery from delta 2-opioid tolerance. 3. Treatment with [D-Ala2]deltorphin II (i.t.) significantly reduced the binding of [tyrosyl-3,5-(3)H(N)]-Tyr-D-Ser-Gly-Phe-Leu-Thr ([3H]-DSLET), a delta 2-opioid receptor agonist ligand, in the spinal cord 3 h after treatment, but binding returned to control levels by 24 h after treatment. However, [3H]-DSLET binding in the spinal cord remained significantly reduced at 24 h if delta-AS oligo (163 pmol) was coadministered with [D-Ala2]deltorphin II (6.4 nmol). 4. Based on these findings, it is concluded that a single stimulation of spinal cord delta 2-opioid receptors by intrathecally-administered [D-Ala2]deltorphin II induces a long-lasting desensitization of delta 2-opioid receptors to [D-Ala2]deltorphin II. Recovery from delta 2-opioid receptor-mediated antinociceptive tolerance apparently depends on replenishment by newly synthesized delta 2-opioid receptor protein rather than immediate reversal of delta 2-opioid receptors.

Role of protein kinase C in desensitization of spinal delta-opioid-mediated antinociception in the mouse.

1. Receptor phosphorylation and down-regulation by protein kinases may be a key event initiating desensitization. The present studies were designed to investigate the effect of a potent protein kinase C (PKC) activator, phorbol 12,13-dibutyrate (PDBu), on antinociception induced by intrathecal (i.t.) administration of a selective delta-opioid receptor agonist [D-Ala2] deltorphin II in the male ICR mouse and on the specific binding of [3H]-[D-Ser2, Leu5]enkephalin-Thr6 (DSLET), a delta-opioid receptor ligand, in the crude synaptic membrane of the spinal cord. 2. Intrathecal (i.t.) pretreatment with PDBu at low doses, which injected alone did not affect the basal tail-flick latency, dose-dependently attenuated the antinociception induced by i.t. administration of [D-Ala2]deltorphin II. The attenuation of i.t.-administered [D-Ala2] deltorphin II-induced antinociception by PDBu was reversed in a dose-dependent manner by i.t. concomitant pretreatment with a specific PKC inhibitor, calphostin C. 3. In the binding experiment, incubation of the crude synaptic membrane of the spinal cord for 2 h at 25 degrees C with PDBu (0.03 to 10 microM) caused a dose-dependent inhibition of the [3H]-DSLET binding. Scatchard analysis of [3H]-DSLET binding revealed that PDBu at 10 microM displayed a 30.7% reduction in the number of [3H]-DSLET binding sites with no significant change in affinity, compared with the non-treatment control, indicating that the activation of membrane-bound PKC by PDBu causes a decrease in the number of specific delta-opioid agonist binding sites. 4. An i.t. injection of [D-Ala2]deltorphin II produced an acute antinociceptive tolerance to the antinociceptive effect of a subsequent i.t. challenge of [D-Ala2]deltorphin II. Concomitant pretreatment with calphostin C markedly prevented the development of acute tolerance to the i.t.-administered [D-Ala2]deltorphin II-induced antinociception. On the other hand, a highly selective protein kinase A (PKA) inhibitor, KT5720, did not have any effect on the development of acute tolerance to [D-Ala2]deltorphin II antinociception. 5. These findings suggest that a loss of specific delta-agonist binding by the activation of PKC by PDBu is involved in the PDBu-induced antinociceptive unresponsiveness to delta-opioid receptor agonist in the mouse spinal cord. Based on the acute tolerance studies, we propose that PKC, but not PKA, plays an important role in the process of homologous desensitization of the spinal delta-opioid receptor-mediated antinociception.

Effects of 2,3-butanedione monoxime in isolated hearts: protection during reperfusion after global ischemia.

The cardiac effects of 2,3-butanedione monoxime on electrical and mechanical function, rhythm, oxygen utilization, and coronary flow responsiveness, particularly during severe ischemia and reperfusion, have not been studied. After perfusing hearts at 55 mm Hg, coronary perfusion was interrupted for 30 minutes and was then reestablished at the control perfusion pressure for 40 minutes. Hearts were divided into four groups (n = 10 each) treated with 0, 3, 5, or 10 mmol/L of 2,3-butanedione monoxime added to the perfusate for 10 minutes before and during ischemia and for the first 10 minutes of reperfusion. An additional nonischemic group served as a time control. Variables monitored were heart rate, atrioventricular conduction time, cardiac rhythm, isovolumetric systolic and diastolic left ventricular pressure, maximum rate of left ventricular pressure change, coronary flow, myocardial oxygen consumption, and the ratio of oxygen delivery to myocardial oxygen consumption. Before ischemia, 2,3-butanedione monoxime significantly decreased isovolumetric left ventricular systolic pressure and increased the ratio of oxygen delivery to myocardial oxygen consumption in a dose-dependent manner, with only slight changes in heart rate and atrioventricular time with 10 mmol/L of 2,3-butanedione, monoxime. After 40 minutes of reperfusion, isovolumetric left ventricular systolic pressure recovered to 81 +/- 5% and 83 +/- 2% of the initial control values for the 5 and 10 mmol/L 2,3-butanedione monoxime groups. This was significantly greater than the recovery for the 0 and 3 mmol/L 2,3-butanedione monoxime groups, 59 +/- 3% and 63 +/- 4%, respectively. Similarly, the duration of ventricular fibrillation and of tachycardia was significantly lower, coronary flow reserve was better preserved, and myocardial oxygen consumption was greater with reperfusion in the 5 and 10 mmol/L 2,3-butanedione monoxime groups than in the 0 mmol/L 2,3-butanedione monoxime group. This study shows that relatively low concentrations of 2,3-butanedione monoxime, given before global ischemia and early during reperfusion of isolated hearts, can protect against dysrhythmias and improve return of myocardial and vascular function.

The effects of hyper- and hypocarbia on intraparenchymal arterioles in rat brain slices.

This investigation examined the direct effects of hyper- and hypocarbia on intracerebral resistance vessels within an intact neuronal synctium. Hippocampal rat brain slices were superfused with artificial cerebrospinal fluid (aCSF). Arterioles were located and diameter changes in response to alterations in aCSF carbon dioxide tension (pCO2) were monitored with videomicroscopy. Microvessels dose dependently dilated and constricted during hyper- and hypocarbia, respectively. A two-fold rise in pCO2 produced a 20% increase in diameter, while a 47% decrease in pCO2 vasoconstricted microvessels by 11%. This is the first model allowing the investigation of the direct actions of physiologic mediators on discrete intracerebral resistance vessels in situ. The results suggest that intracerebral microvessels significantly respond to changes in pCO2 and may be intimately involved in alterations in cerebral vascular resistance.

The effects of graded hypoxia on intraparenchymal arterioles in rat brain slices.

Hypoxia-induced changes in intracerebral arterioles, the major determinants of local cerebral oxygen delivery, are not well understood. Hippocampal arteriolar diameters were measured in rat brain slices using computerized videomicroscopy. In group 1 (control), artificial cerebrospinal fluid oxygen tension (PO2) was maintained at 500 mmHg. In groups 2 and 3, PO2 was gradually reduced to anoxia (95% N2/5% CO2). In group 3, prostaglandin F2a alpha was given to approximate physiological myogenic tone. PCO2 and pH were controlled. Graded hypoxia progressively dilated vessels (PO2 300 mmHg = 2.4 +/- 1.2%, 4.2 +/- 1.6%; PO2 90 mmHg = 15.4 +/- 3.0%, 14.5 +/- 1.8%; groups 2 and 3, respectively). The presence of preconstriction did not influence the extent of hypoxia-induced dilation. This vasorelaxation may be important in maintaining cerebral oxygen delivery during microvascular hypoxia.

Respiratory arrhythmias and airway CO2, lung receptors, and central inspiratory activity.

The purpose of this study was to determine whether hypocapnia affects heart rate secondary to an effect on pulmonary receptors. Dogs were anesthetized and placed on cardiopulmonary bypass. Interrelationships among airway CO2, central inspiratory activity, and lung receptor effects on respiratory-related heart rate changes (respiratory arrhythmias) were studied after vagal efferent activity was increased secondary to baroreceptor stimulation. Hypocapnia, isolated to the lungs, produced an increase in the magnitude of the respiratory arrhythmias observed. Two mechanisms may produce these results. Hypocapnia affects pulmonary receptors, which 1) reflexly alter heart rate and 2) modulate breathing frequency, thus altering the dynamics of the respiratory arrhythmias that were produced. The results also suggested that the reflex increase in heart rate in response to lung inflation and the Hering-Breuer expiratory-facilitatory reflex are either produced by different pulmonary receptors or by the same pulmonary receptors but may be mediated by different central mechanisms.

Effects of hypoxia on adult and neonatal pacemaker rates.

Fetal bradycardia during parturition may result both from autonomic reflex effects and from the direct effect of hypoxia on the myocardium. To compare the relative sensitivities of neonatal and adult sinoatrial nodes to hypoxia, action potentials were recorded simultaneously from isolated neonatal and adult sinoatrial nodal tissues of the guinea pig with intracellular microelectrodes. Action potential rates were measured during normoxia and hypoxia, with and without acidosis, glucose, and epinephrine. Control (PO2 greater than 450 torr) intrinsic pacemaker activity was higher in the neonate than in the adult (296 versus 222 beats per minute). Epinephrine maximally increased rates to similar levels in the two age groups. Hypoxia (PO2 equals 33 torr) markedly lowered adult (44%) and neonatal (35%) rates, but the fall in rates was similar. The addition of acidosis or the removal of glucose during hypoxia produced a greater fall of pacemaker rates in the neonates compared with the adults. The addition of epinephrine during hypoxia caused adult rates to increase to control normoxic levels, but neonatal rates remained significantly depressed below control levels. The results suggest that the neonatal pacemaker node is no better protected against bradycardia during hypoxia alone than is the adult node, but that the neonatal node is more susceptible to bradycardia induced by hypoxia with acidosis or removal of glucose. The hypoxic neonatal node, moreover, responds with a lesser increase in pacemaker rate during epinephrine stimulation than does the adult node.

A continuous noncontact method for measuring in situ vascular diameter with a video camera.

A new, continuous, on-line, video diameter-measuring technique, utilizing a video camera mounted on the sidearm of a stereo microscope, is described. Vessel diameter is derived from changes in the video output signal of the camera or a video recorder when the vessel of interest is displayed horizontally on a monitor and well contrasted with its background. A comparator threshold is set on the filtered video output signal and generates an output pulse that is used to gate horizontal video sync pulses to a digital counter-timer. The number of pulses counted for each video field (no. of horizontal video lines) is proportional to the vessel diameter. The video-derived diameter is calibrated using known standards and correlates well with sonomicrometer-derived diameters of the carotid artery and jugular vein during increasing pressure ramps (r greater than 0.999). The diameter update rate is 60 Hz, and the resolution of the system is one horizontal video line, independent of the vessel size. With suitable magnification and contrast both arteries and veins as small as 200 micron have been measured using this system.

Effect of hemodilution on RBC velocity, supply rate, and hematocrit in the cerebral capillary network.

The effect of isovolemic hemodilution on the circulation of red blood cells (RBCs) in the cerebrocortical capillary network was studied by intravital videomicroscopy with use of a closed-cranial-window technique in the rat. Velocity and supply rate of RBCs were measured by tracking the movement and counting the number of fluorescently labeled cells. Arterial blood was withdrawn in increments of 2 ml and replaced by serum albumin. Arterial blood pressure was maintained constant with an infusion of methoxamine. Both velocity and supply rate of RBCs increased, by approximately equal amounts, as arterial hematocrit was reduced from 44 to 15%. The maximum increase in RBC velocity was 4.6 and in RBC supply rate was 5.2 times the baseline value. Calculated lineal density of RBC, an index of capillary hematocrit, did not change with hemodilution. The results suggest that RBC flow and oxygen supply in the cerebral capillary network are maintained during isovolemic hemodilution. The "optimal hematocrit" is as low as 15%.

Effects of chronic right-to-left cardiac shunt on hypoxic sensitivity of mongrel dogs.

Resting ventilation (VI), blood gases, hypoxic sensitivity, and the ventilatory responses to intravenous sodium cyanide (NaCN, 100 micrograms/kg), doxapram (DOX, 500 micrograms/kg), and dopamine (DOPA, 20 micrograms/kg) were analyzed in four normal mongrel dogs (group I-N) and seven mongrel dogs with chronic (5-11 yr) right-to-left cardiac shunt (group II). The group I-N animals were also studied during steady-state isocapnic hypoxia (group I-H). The shunt procedure used for these studies produced a model for ventilatory studies during chronic shunt hypoxemia. The increases in VI per percent decrease in O2 saturation, which occurred during a four-breath N2 test, were 30, 43, and 13 ml X kg-1 X min-1 in groups I-N, I-H, and II, respectively. The decrease in hypoxic sensitivity of the group II animals, compared with groups I-N and I-H, occurred in the presence of an increase in PaCO2 from 21.9 to 26.0 Torr during the four-breath N2 test. A decrease in PaCO2 from 34.7 to 30.0 and from 33.6 to 30.4 Torr was observed in groups I-N and I-H. The response to DOX, a general analeptic agent, was greatest in group II and least in group I-N. However, the ventilatory responses to NaCN and DOPA were not sufficiently different among the three groups to suggest a difference in carotid body function as assessed by these drugs.

Pretreatment with beta-endorphin facilitates the attenuation of delta-opioid receptor-mediated antinociception caused by delta-opioid receptor antisense oligodeoxynucleotide.

Intracerebroventricular (i.c.v.) pretreatment of male ICR mice with beta-endorphin (0.6 nmol) or intrathecal (i.t.) pretreatment with antisense oligodeoxynucleotide to delta-opioid receptor mRNA (163 pmol) alone given 24 h earlier did not have any effect on i.t. administered delta-opioid receptor agonist [D-Ala2]deltorphin II (6.4 nmol)-induced antinociception. However, a concomitant i.c.v. pretreatments with beta-endorphin (0.08-0.6 nmol) and i.t. pretreatment with delta-opioid receptor antisense oligodeoxynucleotide (163 pmol) for 24 h dose-dependently attenuated i.t. challenged [D-Ala2]deltorphin II-induced antinociception. A concomitant i.c.v. pretreatment with mu-opioid receptor agonist [D-Ala2,N MePhe4,Gly(ol)5]enkephalin (DAMGO) or kappa-opioid receptor agonist U50,488H and i.t. pretreatment with delta-opioid receptor antisense oligodeoxynucleotide for 24 h did not affect i.t. challenged [D-Ala2]deltorphin II-induced antinociception. beta-Endorphin given supraspinally has been documented to release [Met5]enkephalin acting on delta-opioid receptors in the spinal cord. Our results indicate that supraspinal pretreatment with beta-endorphin selectively causes a loss of spinal delta-opioid receptor-mediated antinociception in mice receiving delta-opioid receptor antisense oligodeoxynucleotide.

Pretreatment with pertussis toxin spinally, but not supraspinally, blocks the cold water swimming-induced antinociception in the mouse.

Mice exposed to cold water swimming (4 degrees C) for 3 min produced a marked antinociception. Experiments were designed to determine whether pretreatment with pertussis toxin given intrathecally (i.t.) or intracerebroventricularly (i.c.v.) attenuates cold water swimming-induced antinociception in male ICR mice. Antinociception was measured by the tail-flick test 7 min after cold water swimming. I.t. pretreatment with pertussis toxin at a dose of 0.5 microgram for 24-96 h caused a time-dependent attenuation of cold water swimming-induced antinociception. Moreover, i.t. pretreatment with pertussis toxin at doses from 0.125 to 0.5 microgram for 96 h attenuated cold water swimming-induced antinociception in a dose-dependent manner. However, i.c.v. pretreatment with pertussis toxin at doses from 0.125 to 0.5 microgram for 24-96 h did not affect the cold water swimming-induced antinociception. The present results suggest that pertussis toxin-sensitive Gi/G(o) proteins in spinal cord, but not at the supraspinal sites, are involved in cold water swimming-induced antinociception.

Antisense oligodeoxynucleotide to a delta-opioid receptor selectively blocks the spinal antinociception induced by delta-, but not mu- or kappa-opioid receptor agonists in the mouse.

An antisense oligodeoxynucleotide (A-oligo) to delta-opioid receptor mRNA was utilized to block the expression of mouse delta-opioid receptor in the spinal cord of male ICR mice. Intrathecal treatment with A-oligo (1.6-163 pmol) dose-dependently attenuated the antinociception induced by i.t. administered DPDPE ([D-Pen2,5]enkephalin) or [D-Ala2]deltorphin II, delta-opioid receptor agonist, without affecting the antinociception induced by DAMGO ([D-Ala2-MePhe4,Gly(ol)5]enkephalin) or U50,488H, respective mu- or kappa-opioid receptor agonists. Scrambled sense oligodeoxynucleotide (163 pmol) was ineffective against the tail-flick inhibition induced by DPDPE,[D-Ala2]deltorphin, DAMGO or U50,488H. The studies confirm previous pharmacological studies at the molecular level indicating a distinct delta-opioid receptor for antinociception in the spinal cord.

Postnatal remodeling of the leptomeningeal vascular network as assessed by intravital fluorescence video-microscopy in the rat.

An intriguing characteristic of the ontogenic development of the cerebral vasculature is the rapid differentiation of the neonatal leptomeningeal vascular plexus into the mature, adult network form. The physiological and cellular mechanisms of this cerebrovascular remodeling process are unclear. The objective of this work was to determine and correlate changes in vascular density, network pattern and flow velocity in leptomeningeal microvessels of the rat during postnatal development in vivo. To this end, microvascular diameter, segment length, and vascular density of reconstructed leptomeningeal networks were measured from video-recordings of the microcirculation visualized through a cranial window in 0-15-day-old Sprague-Dawley rats. The velocity of erythrocytes in the microvessels was measured by frame to frame tracking of fluorescently labeled red blood cells. We found that surface vascular density (total vessel length per area), node density and segment density (object per area) decreased significantly by the second week after birth. Anastomosing vascular polygons, characteristic to newborn networks, became less numerous and larger in diameter during the postnatal 2-week period, indicating progressive rarefaction of the networks. Vessel diameter and red cell velocity showed transient increases at 1.5 weeks. The velocity/diameter ratio (V/D), an index of wall shear rate, increased by the age of 1.5 weeks and remained unchanged afterwards. There was a negative correlation between V/D and diameter at 1 week; this relationship was reversed to a positive correlation at 2 weeks. We conclude that postnatal remodeling of the leptomeningeal vascular network is associated with rarefaction and an adaptation of vessel caliber to wall shear rate. These changes may contribute to arterio-venous differentiation and redistribution of blood flow from the superficial to the intracortical vasculature in the developing brain.

Substance abuse by anesthesiology residents.

A 1989 cross-sectional substance abuse survey of 260 former anesthesiology residents of the Medical College of Wisconsin (MCW) during the previous 30 years yielded 183 responses (70.3%). Over three-fourths (77.2%) of those who responded reported that they had used alcohol when they were residents; 20.0% had used marijuana; and 15.7% had used cocaine. Forty-three of the 178 respondents had used unprescribed psychoactive drugs. Twenty-nine (15.8%) had been self-admitted problematic substance abusers during their residencies: 23, alcohol dependent and six, drug dependent; among the latter were four with a dual (alcohol and drug) dependency. More than 85% considered the drug policy information available during their residencies had been inadequate; institutional drug-control policies were rated "fair-to-poor" by more than 70%. Thirty-five of the residents had observed their teachers using alcohol and/or other drugs to the detriment of their teaching; approximately one-third of these infractions had gone unreported.