Regulations of opioid dependence by opioid receptor types

Three major types of opioid receptors, designated mu, delta, and kappa, are widely expressed in the CNS. Development of selective receptor ligands and recent cloning of each receptor have contributed greatly to our increasing knowledge of the neuropharmacological profile of each opioid receptor type. It is of interest to note that they include noncompetitive and allosteric interactions among their types. This review focuses on the functional interaction among these opioid receptor types that contribute to opioid dependence. Various studies provide arguments to support substantial roles for mu-opioid receptors and the possible involvement of delta-opioid receptors in the development of physical and psychological dependence on morphine. Noradrenergic transmission originating in the locus coeruleus is most likely to play the primary causal role in the expression of physical dependence on morphine. In contrast, many studies have pointed to the mesolimbic dopaminergic pathway projecting from the ventral tegmental area to the nucleus accumbens as a critical site for the initiation of psychological dependence on opioids. It is noteworthy as the broad existence of opposing interactions between mu/delta- and kappa-receptors in the brain. The activation of kappa-receptors leads to the suppression of unpleasant mu/delta-mediated side effects such as the rewarding effect. Considering the functional interaction among opioid receptor types, the co-administration of morphine-like compounds with kappa-receptor agonists may constitute a preferable and superior approach to the treatment of pain with fewer side effects.

Dopexamine: a novel agonist at peripheral dopamine receptors and beta 2-adrenoceptors

Dopexamine is an agonist at peripheral dopamine receptors and at beta 2-adrenoceptors. Dopexamine has approximately one-third the potency of dopamine in stimulating the vascular DA1-receptor in the dog, resulting in a fall in renal vascular resistance of 20% at 2.3 X 10(-8) mol kg-1 (i.a.). Prejunctional DA2-receptors are also stimulated by dopexamine, resulting in a reduction of neurogenic vasoconstriction in the rabbit isolated ear artery (IC50 of 1.15 X 10(-6)M) and of neurogenic tachycardia in the cat (ID50 of 5.4 X 10(-8) mol kg-1, i.v.), with a potency six and four times less respectively than that of dopamine. By contrast, dopexamine is approximately 60 times more potent than dopamine as an agonist at the beta 2-adrenoceptor of the guinea-pig isolated tracheal chain, with an EC50 of 1.5 X 10(-6)M. Both dopexamine and dopamine are weak agonists at the guinea-pig atrial beta 1-adrenoceptor over the concentration range 10(-7) to 10(-4) M, but dopexamine has an intrinsic activity of only 0.16 relative to dopamine. Dopexamine does not stimulate postjunctional alpha 1- or alpha 2-adrenoceptors in the canine isolated saphenous vein, whereas dopamine is an agonist, approximately 120 times less potent than noradrenaline. Unlike dopamine and salbutamol, dopexamine does not cause arrhythmias in the guinea-pig isolated perfused heart at doses of up to 10(-5) mol, which is a thousand times the minimum cardiostimulant dose. The combination of agonist properties at peripheral dopamine receptors and at beta 2-adrenoceptors, with little or no activity at alpha- and beta 1-adrenoceptors gives dopexamine a novel pharmacological profile. This may confer advantages over dopamine in the treatment of acute heart failure.

Randomised control trial of pH buffered lignocaine with adrenaline in outpatient operations

Bicarbonate buffering of local anaesthetics is known to significantly decrease the pain of their administration and yet few practising surgeons do so. A double-blind randomised cross-over clinical trial was conducted to confirm the practicality and efficacy of bicarbonate buffering of lignocaine with adrenaline in the setting of a busy local anaesthetic operating theatre. 40 patients received either buffered or control local anaesthetic solutions in equivalent sites on opposite sides of the body. The pain of each injection was rated from 0 (no pain) to 10 (extreme pain). The mean pain score for the buffered solution was significantly lower than the control solution (3.06 vs 4.34, P = 0.002). Bicarbonate buffering of lignocaine with adrenaline is effective, inexpensive and simple; its widespread use should be encouraged.

Extracellular ATP inhibits adrenergic agonist-induced hypertrophy of neonatal cardiac myocytes

We have previously shown that extracellular ATP, like norepinephrine (NE) and many other hypertrophy-inducing agents, increases expression of the immediate-early genes c-fos and junB in cultured neonatal cardiac myocytes but that the intracellular signaling pathways activated by ATP and responsible for these changes differ from those stimulated by NE. Furthermore, whereas NE increases incorporation of [14C]phenylalanine (14C-Phe) and cell size in neonatal cardiomyocytes, ATP does not. Since ATP is coreleased with NE from sympathetic nerve endings in the heart, we investigated whether ATP could modulate cardiac hypertrophy induced by adrenergic agonists, such as NE. We report in the present study that extracellular ATP inhibited the increase in incorporation of 14C-Phe into cellular protein and the increase in cell size in neonatal rat cardiac myocytes that was induced by NE, phenylephrine (PE), basic fibroblast growth factor, or endothelin-1. This inhibition was dose dependent, occurred predominantly through P2 purinergic receptors, and was observed even when cells were treated with ATP for as little as 1 hour before the addition of the hypertrophy-inducing agent. ATP also selectively affected changes in gene expression associated with hypertrophy. It prevented PE-stimulated increases in atrial natriuretic factor and myosin light chain-2 mRNA levels, while appearing to augment basal and PE-stimulated skeletal alpha-actin mRNA levels. ATP alone increased sarcoplasmic reticulum Ca2+-ATPase mRNA levels but had no effect when added with PE. ATP did not significantly affect the level of the constitutively expressed mRNA for GAPDH. Neither the PE-stimulated increase in immediate-early gene expression nor the initial induction of mitogen-activated protein kinase activity by PE was inhibited by ATP. These results demonstrate that extracellular ATP can inhibit hypertrophic growth of neonatal cardiac myocytes and differentially alter the changes in gene expression that accompany hypertrophy.

Evidence that baroreflex feedback influences long-term incidental visual memory in men

Sympathetic nervous system (SNS) activity at the time of acquisition is associated with human memory. However, rather than SNS activity per se, it may be afferent baroreflex feedback that is responsible for this effect. A pharmacological design was employed to unload (SNP, sodium nitro-prusside) and load (norepinephrine) baroreceptors. In addition to two placebo periods, epinephrine and esmolol (a peripherally acting beta1-blocker) served as control conditions for altered cardiac perception. During drug infusion blood pressure, heart rate, and perception of heartbeat were tested. Twenty-four healthy men were participated. The participants viewed emotional slides while their electromyographic eye blink responses to random noise bursts were measured (affective startle modulation paradigm) to determine potential drug impact on emotional processing. Subjects were not informed that memory testing would take place after 4 weeks. Drugs did not impact startle, thus indicating unbiased emotional processing at the time of acquisition. Norepinephrine had no effect on heartbeat perception, but improved (p = .002) recognition memory. SNP (p = .0001) increased heartbeat perception but impaired (p = .038) recognition memory. Epinephrine, on the other hand, increased heartbeat perception (p = .0001) yet did not impair but partially improve memory (effect on high arousing pictures only: p = .05). Heartbeat perception in the placebo condition did not correlate with recognition memory (p's > .5). We suggest that baroreflex unloading, with subsequent feedback activation of the SNS, impairs long-term incidental visual recognition memory in humans while baroreflex loading enhances it. Further, we propose that these memory effects are neither secondary to cardiac sensations that accompany SNS activation nor to altered emotional picture processing at the time of acquisition.

β3-Adrenergic receptor agonist treats rotator cuff fatty infiltration by activating beige fat in mice

BACKGROUND

Rotator cuff (RC) muscle atrophy and fatty infiltration (FI) are independent factors correlated with failure of attempted tendon repair in larger RC tears. However, there is no effective treatment for RC muscle atrophy and FI at this time. The recent discovery of beige adipose tissue (BAT) in adults shed light on a new avenue in treating obesity and excessive fat deposition by promoting BAT activity. The goal of this study was to define the role of intramuscular BAT in RC muscle FI and the effect of β₃-adrenergic receptor agonists in treating RC muscle FI by promoting BAT activity.

MATERIALS AND METHODS

Three-month-old wild-type C57BL/6J, platelet derived growth factor receptor-alpha (PDGFRα) green fluorescent protein (GFP) reporter and uncoupling protein 1 (UCP-1) knockout mice underwent a unilateral RC injury procedure, which included supraspinatus (SS) and infraspinatus tendon resection and suprascapular nerve transection. To stimulate BAT activity, amibegron, a selective β₃-adrenergic receptor agonist, was administered to C57BL/6J mice either on the same day as surgery or 6 weeks after surgery through daily intraperitoneal injections. Gait analysis was conducted to measure forelimb function at 6 weeks or 12 weeks (in groups receiving delayed amibegron treatment) after surgery. Animals were killed humanely at 6 weeks (or 12 weeks for delayed amibegron groups) after surgery. SS muscles were harvested and analyzed histologically and biochemically.

RESULTS

Histologic analysis of SS muscles from PDGFRα-GFP reporter mice showed that PDGFRα-positive fibroadipogenic progenitors in RC muscle expressed UCP-1, a hallmark of BAT during the development of FI after RC tears. Impairing BAT activity by knocking out UCP-1 resulted in more severe muscle atrophy and FI with inferior forelimb function in UCP-1 knockout mice compared with wild-type mice. Promoting BAT activity with amibegron significantly reduced muscle atrophy and FI after RC tears and improved forelimb function. Delayed treatment with amibegron reversed muscle atrophy and FI in muscle.

CONCLUSIONS

Fat accumulated in muscle after RC tears possesses BAT characteristics. Impairing BAT activity results in worse RC muscle atrophy and FI. Amibegron reduces and reverses RC atrophy and FI by promoting BAT activity.

Local anesthesia for prostate brachytherapy

PURPOSE

To demonstrate the technique and feasibility of prostate brachytherapy performed with local anesthesia only.

METHODS AND MATERIALS

A 5 by 5 cm patch of perineal skin and subcutaneous tissue is anesthetized by local infiltration of 10 cc of 1% lidocaine with epinephrine, using a 25-gauge 5/8-inch needle. Immediately following injection into the subcutaneous tissues, the deeper tissues, including the pelvic floor and prostate apex, are anesthetized by injecting 15 cc lidocaine solution with approximately 8 passes of a 20-gauge 1.0-inch needle. Following subcutaneous and peri-apical lidocaine injections, the patient is brought to the simulator suite and placed in leg stirrups. The transrectal ultrasound (TRUS) probe is positioned to reproduce the planning images and a 3.5- or 6.0-inch, 22-gauge spinal needle is inserted into the peripheral planned needle tracks, monitored by TRUS. When the tips of the needles reach the prostatic base, about 1 cc of lidocaine solution is injected in the intraprostatic track, as the needle is slowly withdrawn, for a total volume of 15 cc. The implants are done with a Mick Applicator, inserting and loading groups of two to four needles, so that a maximum of only about four needles are in the patient at any one time. During the implant procedure, an additional 1 cc of lidocaine solution is injected into one or more needle tracks if the patient experiences substantial discomfort. The total dose of lidocaine is generally limited to 500 mg (50 ml of 1% solution).

RESULTS

To date, we have implanted approximately 50 patients in our simulator suite, using local anesthesia. Patients' heart rate and diastolic blood pressure usually showed moderate changes, consistent with some discomfort. The time from first subcutaneous injection and completion of the source insertion ranged from 35 to 90 minutes. Serum lidocaine levels were below or at the low range of therapeutic. There has been only one instance of acute urinary retention in the patients treated so far, and no unplanned admissions to the hospital or need to reschedule a patient to be implanted under general or spinal anesthesia.

CONCLUSIONS

The substitution of local anesthesia has facilitated rapid introduction of a high-volume brachytherapy program at an institution that previously had none, without requiring the allocation of significant operating room time. Although the patients reported here were implanted without conscious sedation, we are starting to try various sedatives and analgesics for patients who we anticipate will have substantial anxiety with the procedure.

β2-Adrenergic Receptor Signaling Pathway Stimulates the Migration and Invasion of Cancer Cells via Src Activation

Chronic stress has been reported to stimulate the release of catecholamines, including norepinephrine (NE) and epinephrine (E), which promote cancer progression by activating the adrenergic receptor (AR). Although previous studies showed that β2-AR mediated chronic stress-induced tumor growth and metastasis, the underlying mechanism has not been fully explored. In this study, we aimed to investigate the molecular mechanism by which β2-AR exerts a pro-metastatic function in hepatocarcinoma (HCC) cells and breast cancer (BC) cells. Our results showed that Hep3B human HCC cells and MDA-MB-231 human BC cells exhibited the highest ADRB2 expression among diverse HCC and BC cell lines. NE, E, and isoprenaline (ISO), adrenergic agonists commonly increased the migration and invasion of Hep3B cells and MDA-MB-231 cells. The phosphorylation level of Src was significantly increased by E/NE. Dasatinib, a Src kinase inhibitor, blocked E/NE-induced migration and invasion, indicating that AR agonists enhanced the mobility of cancer cells by activating Src. ADRB2 knockdown attenuated E/NE-induced Src phosphorylation, as well as the metastatic ability of cancer cells, suggesting the essential role of β2-AR. Taken together, our results demonstrate that chronic stress-released catecholamines promoted the migration and invasion of HCC cells and BC cells via β2-AR-mediated Src activation.

Quality of domestic cat semen collected by urethral catheterization after the use of different alpha 2-adrenergic agonists

OBJECTIVES

We compared the effects of two alpha (α)2-adrenergic agonists on semen traits.

METHODS

In this study, 13 adult domestic cats were divided into two experimental groups, according to the chemical ejaculation protocol used: the first group received medetomidine hydrochloride (100 µg/kg) and ketamine (5000 µg/kg); the second group received dexmedetomidine hydrochloride (25 µg/kg) and ketamine (5000 µg/kg), both by the intramuscular route.

RESULTS

The animals responded positively (P >0.05) to chemical collection. Seminal parameters evaluated included volume, sperm vigor, total motility, progressive motility, sperm concentration, and the structural and functional integrity of the plasma membrane; sperm morphology values did not differ between groups (P >0.05).

CONCLUSIONS AND RELEVANCE

The results indicated that dexmedetomidine is a more viable and economical alternative to medetomidine in domestic cats submitted to semen collection by urethral catheterization. Semen collection by urethral catheterization after using α2-adrenergic agonists is a recently developed technique in feline species that is considered to be quick and highly applicable to assisted reproduction programs in felids.

Electromechanical effects of caffeine in failing human ventricular myocardium

We studied, using standard microelectrode technique, the effects of caffeine alone and in conjunction with epinephrine in ventricular myocardial fibers obtained from the failing hearts of 12 recipients of heart transplant. Results revealed that caffeine (1-3 mM) prolonged slightly the duration of fast response action potential near final repolarization and the twitch curve but slightly increased, or even decreased, the twitch force. Epinephrine (3 microM) induced a submaximal positive inotropic effect in myocardial fibers obtained from the failing hearts. Caffeine at 1 mM significantly potentiated the force of contraction and accelerated the rate of twitch relaxation increased by epinephrine. Increasing concentration of caffeine to 3 mM in the presence of epinephrine did not enhance further the twitch force but rather induced the delayed after-depolarization in two of eight experiments. In a preparation from one patient with dilated cardiomyopathy, the combination of caffeine and epinephrine induced repetitive triggered rhythms. The present findings suggest that, in human ventricular myocardium obtained from certain patients transplanted for congestive heart failure, caffeine could induce positive inotropy and triggered automaticity through a potentiation of the actions of catecholamines.

Systemic postganglionic adrenergic studies do not distinguish Parkinson's disease from multiple system atrophy

BACKGROUND

Multiple system atrophy (MSA) affects the preganglionic adrenergic neuron and Parkinson's disease (PD) involves the postganglionic counterpart. Widespread postganglionic denervation should result in denervation supersensitivity and a failure of the axon to release norepinephrine (NE). We examined if pharmacological dissection of the adrenergic neuron can distinguish between MSA and PD.

METHOD

We measured blood pressure, heart rate, and plasma NE responses to direct (phenylephrine) and indirect (tyramine) acting adrenergic agonists in 15 patients with probable MSA, 16 patients with idiopathic PD, and 16 age- and gender-matched controls.

RESULTS

Baroreflex sensitivity was impaired in MSA and intact in PD. Pressor responses to phenylephrine (direct acting) were higher in MSA (p<0.01) and PD patients (p=0.04) than in controls. Blood pressure responses to tyramine (indirect acting) were increased in MSA only (p<0.01). Tyramine increased plasma catecholamine levels in all groups with no significant differences between groups.

CONCLUSION

There is denervation supersensitivity in PD patients that is, however, insufficient to shift the dose-response curve to the left. The excessive pressor responses to both tyramine and phenylephrine in MSA are due to baroreflex failure. We conclude that this diagnostic approach lacks sufficient sensitivity to differentiate PD and MSA.

Mental well-being in alcohol withdrawal: relationship to alpha2-adrenoceptor function

The possible relationship between postsynaptic alpha2-adrenoceptor function, as assessed by the growth hormone (GH) response to clonidine (CLON) and aspects of mental well-being by self-report of mood using the Swedish Mood Adjective Check List, was investigated in alcohol-dependent patients in the early withdrawal period. Patients had blunted GH responses to CLON and worse mental well-being than control subjects immediately after the end of alcohol intake. No relation was found between mental well-being and postsynaptic alpha2-adrenoceptor function. After 1 week, the GH responses to CLON remained blunted, whereas the state of mental well-being had improved to levels similar to those of control subjects. The results further support a downregulated alpha2-adrenoceptor function during 1 week of alcohol withdrawal. Furthermore, even if subsensitive postsynaptic alpha2-adrenoceptor function was not generally related to state of mood, patients with the lowest postsynaptic alpha2-adrenoceptor function reported the highest levels in the dimensions pleasantness/unpleasantness and activation/deactivation when sober.

Sulfate radical induced degradation of β2-adrenoceptor agonists salbutamol and terbutaline: Phenoxyl radical dependent mechanisms

The present study investigated the reactivity and oxidation mechanisms of salbutamol (SAL) and terbutaline (TBL), two typical β2-adrenoceptor agonists, towards sulfate radical (SO₄^-) by using photo-activated persulfate (PS). The reaction pathways and mechanisms were proposed based on products identification using high resolution HPLC-ESI-MS, laser flash photolysis (LFP) and molecular orbital calculations. The results indicated that SO₄^- was the dominant reactive species in the UV/PS process. The second-order rate constants of sulfate radical reaction with SAL and TBL were measured as (3.7 ± 0.3) × 10⁹ and (4.2 ± 0.3) × 10⁹ M^-1 s^-1 by LFP, respectively. For both SAL and TBL, phenoxyl radicals were found to play key roles in the orientation of the primary pathways. For SAL, a benzophenone derivative was generated by oxidation of the phenoxyl radical. However, in the case of TBL, the transformation of the phenoxyl radical into benzoquinone was impossible. Instead, the addition of OSO₃H on the aromatic ring was the major pathway. The same reactivity pattern was observed in the case of TBL structural analogs resorcinol and 3,5-dihydroxybenzyl alcohol. Our results revealed that basic conditions inhibited the decomposition of SAL and TBL, while, increasing PS dose enhanced the degradation. The present work could help for a better understanding of the difference in oxidation reactivity of substituted phenols widely present in natural waters.

Moxonidine: some controversy

Initially it was considered that moxonidine, like clonidine, acted at central (2)-adrenoceptors to reduce blood pressure. With the characterisation of imidazoline binding sites distinct from (2)-adrenoceptors, the consensus became that moxonidine was acting predominantly at imidazoline I(1) receptors in the rostral ventrolateral medulla to lower blood pressure. Moxonidine acts at prejunctional (2)-adrenoceptors on sympathetic nerve endings to decrease noradrenaline release and this may contribute to its ability to lower blood pressure. The predominant site of action of moxonidine may also depend on route of administration, with imidazoline I(1) receptors being predominant after central, and (2)-adrenoceptors predominant after systemic administration. The controversy over the mechanism and site of action with moxonidine is ongoing. In animal models, moxonidine lowers blood pressure, reduces cardiac hypertrophy and remodelling, reduces cardiac arrhythmias and increases blood flow in cerebral ischaemia. Moxonidine also has beneficial effects in animal models of diabetes and kidney disease. Moxonidine increases sodium and water excretion in rats, but not humans. Animal studies indicate that moxonidine may be useful in the treatment of glaucoma by reducing intra-ocular pressure. Animal studies show that moxonidine may also be effective in pain and in ethanol withdrawal. In humans, the pharmacokinetics of moxonidine are of the one-compartment model with first-order absorption. Renal elimination is the major route of elimination and individual titration of moxonidine is needed in patients with renal impairment. There is overwhelming evidence that moxonidine is a safe and effective antihypertensive. A large clinical trial of moxonidine in heart failure, MOXCON, was stopped because of excessive deaths in the moxonidine group. Moxonidine should not be used in patients with heart failure, but there are no obvious reasons to stop its use as an antihypertensive, or its development for other clinical uses.

The Guinea Pig Blinking Test: a comparison with human responses

The Guinea Pig Blinking Test (2) was presented as a model for the selection and development of comfortable ocular formulations. This study compares human nociceptive responses and the blinking response of the guinea pig to different concentrations of a topically applied ophthalmic drug, sulfacetamide. The number of human subjects noting pain upon instillation of various concentrations of sulfacetamide (3) was compared to the blinking responses of guinea pigs treated with 2.5%-17.5% sulfacetamide. The number of blinks was counted over a period of 5 minutes following (1) saline (0.9% NaCl), and (2) 30-60 minutes later a test solution. A Blinking Index (B.I.) = blinks drug/blinks saline was calculated for each animal. The dose/response curves of both humans and guinea pigs were almost identical, showing a threshold at 5% sulfacetamide, followed by a linear increase, reaching a maximum at 12.5%-15% sulfacetamide. A 2.5% solution that elicited pain in 10% of human subjects yielded a B.I. = 1.04 +/- 0.05, whereas a 12.5% solution that elicited pain in 95% of human subjects yielded a B.I. = 1.61 +/- 0.13 (mean +/- S.E., n = 10, P < 0.05). The strong linear relationship between the guinea pig blinking response and the human perception of pain, following identical treatment with a topical ophthalmic drug, demonstrates that this animal test can be useful in predicting the degree of ocular discomfort of human subjects.

Inhibition of human platelet function by sulfatides

Sulfatides are glycolipid constituents of human platelet cell membranes and have been shown to interact with platelet-binding proteins involved in hemostasis. Because little is known about the physiological role of sulfatides in platelet function, the effect of sulfatide on platelet adhesion, aggregation, release, and ristocetin-induced platelet agglutination (RIPA) was studied. These processes are inhibited when exogenous sulfatide is present in vitro. Inhibition of aggregation induced by collagen, thrombin, and ristocetin by sulfatide was dose dependent. Adenosine diphosphate-mediated adhesion and aggregation were not significantly affected by sulfatide, nor was serotonin- and epinephrine-mediated aggregation. Collagen mediate release of serotonin was reduced sulfatide. RIPA demonstrated dose-dependent inhibition in response to sulfatide. These results suggest that sulfatide may play a role in modulating platelet activation.

Modulation of renal blood flow by endogenous endothelin-1 in conscious rabbits with left ventricular dysfunction

The current study addresses the functional status and role of the endothelin ET(A) receptor for renal vascular function in rabbits with and without heart failure (epinephrine-induced cardiomyopathy). Under baseline conditions, the ET(A) receptor antagonist BQ-123 did not change basal renal hemodynamics, but completely prevented endothelin-1 (ET-1)-induced renal vasoconstriction. In heart failure, in the presence of elevated plasma ET-1 concentrations (P < .05), renal vasoconstriction in response to exogenous ET-1 was intact. Unlike under baseline conditions, ET(A) receptor antagonism markedly increased renal blood flow (P <.05) and decreased renal vascular resistance (P < .05) in heart failure. The current study provides new insight into the pathophysiology of renal vasoconstriction associated with heart failure and the specific role of the renal ET(A) receptor in this pathophysiologic adaptation.

Deep eutectic solvents combined with beta-cyclodextrin derivatives for chiral separation of typical adrenergic receptor agonists by capillary electrophoresis with amperometric detection

Enantioseparation has always been one of the research hotspots and difficulties in the field of modern separation science. In this work, a binary chiral electrophoretic separation system was constructed using deep eutectic solvents (DESs) coupled with beta-cyclodextrin derivatives based on capillary electrophoresis with amperometric detection system, and five groups of typical adrenergic receptor agonists (adrenaline, salbutamol, isoproterenol, norepinephrine and terbutaline) were selected as the model enantiomers. The effects of additive types and contents of DESs and cyclodextrins, and the pH value and concentration of the running buffer on the resolution of the selected chiral compounds were investigated in detail. The mechanism of DESs improving separation was explored preliminarily by means of UV spectrophotometry, which was further verified based on the comparison of single and mixed components of choline chlorine-urea DES. Under the optimum conditions, the relative standard deviations for inter-day and intra-day repeatability of the migration time, peak area and resolution for adrenaline and salbutamol were within 8.7%, and the limits of detection reached 0.030 μg mL-1 (S/N = 3). The recovery data were in the range of 96.3-118.7%. The developed methods have been applied for the analyses of (+)-adrenaline hydrochloride injection and (±)-salbutamol aerosol. This binary chiral electrophoretic separation system by CE-AD has high detection sensitivity and low analytical cost, providing an alternative for the separation and analysis of chiral drugs.

β3 Adrenoceptor Agonism Prevents Hyperoxia-Induced Colonic Alterations

Oxygen level is a key regulator of organogenesis and its modification in postnatal life alters the maturation process of organs, including the intestine, which do not completely develop in utero. The β3-adrenoreceptor (β3-AR) is expressed in the colon and has an oxygen-dependent regulatory mechanism. This study shows the effects of the β3-AR agonist BRL37344 in a neonatal model of hyperoxia-driven colonic injury. For the first 14 days after birth, Sprague-Dawley rat pups were exposed to ambient oxygen levels (21%) or hyperoxia (85%) and treated daily with BRL37344 at 1, 3, 6 mg/kg or untreated. At the end of day 14, proximal colon samples were collected for analysis. Hyperoxia deeply influences the proximal colon development by reducing β3-AR-expressing cells (27%), colonic length (26%) and mucin production (47%), and altering the neuronal chemical coding in the myenteric plexus without changes in the neuron number. The administration of BRL37344 at 3 mg/kg, but not at 1 mg/kg, significantly prevented these alterations. Conversely, it was ineffective in preventing hyperoxia-induced body weight loss. BRL37344 at 6 mg/kg was toxic. These findings pave the way for β3-AR pharmacological targeting as a therapeutic option for diseases caused by hyperoxia-impaired development, typical prematurity disorders.