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Journal of Veterinary Cardiology : the... Jun 2024A nine-year-old spayed female domestic shorthair cat with a previous diagnosis of hypertrophic cardiomyopathy and treated for one month with atenolol (6.25 mg q 12 h)...
A nine-year-old spayed female domestic shorthair cat with a previous diagnosis of hypertrophic cardiomyopathy and treated for one month with atenolol (6.25 mg q 12 h) was referred for respiratory distress and anorexia. The cat was diagnosed with pulmonary oedema secondary to obstructive hypertrophic cardiomyopathy. After stabilisation, she was discharged with furosemide (1 mg/kg q 12 h), clopidogrel (18.75 mg q 24 h), atenolol (6.25 mg q 12 h), and mirtazapine (2 mg/cat q 24 h) to increase appetite. At recheck, the cat was lethargic and presented with severe bradycardia with a junctional escape rhythm and ventriculoatrial conduction. The mirtazapine was discontinued due to its possible side-effects on cardiac rhythm. After three days, the atenolol was halved because the bradyarrhythmia was still present. After 10 days, the rhythm returned to sinus; atenolol was reintroduced twice daily with no further side-effects. The absence of a sinus rhythm with a junctional escape rhythm and P' retroconduction is compatible with a third-degree sinus block or a sinus standstill; the differentiation of these rhythm disturbances is impossible, based on the surface electrocardiogram (ECG). The sinus rhythm was restored after mirtazapine was withdrawn. However, it is not possible to rule out the role of the atenolol or the combined effect of the two drugs. The cat was affected by hypertrophic cardiomyopathy, and the role of myocardial remodelling cannot be excluded. This is the first time that a bradyarrhythmia consequent to the treatment with atenolol and mirtazapine was described in a cat.
Topics: Female; Mirtazapine; Animals; Atenolol; Cats; Cat Diseases; Cardiomyopathy, Hypertrophic; Bradycardia; Mianserin; Adrenergic beta-1 Receptor Antagonists
PubMed: 38735230
DOI: 10.1016/j.jvc.2024.03.003 -
International Journal of Molecular... Apr 2024Chronic postsurgical pain (CPSP) following total knee arthroplasty (TKA) and total hip arthroplasty (THA) is a prevalent complication of joint replacement surgery which... (Review)
Review
Chronic postsurgical pain (CPSP) following total knee arthroplasty (TKA) and total hip arthroplasty (THA) is a prevalent complication of joint replacement surgery which has the potential to decrease patient satisfaction, increase financial burden, and lead to long-term disability. The identification of risk factors for CPSP following TKA and THA is challenging but essential for targeted preventative therapy. Recent meta-analyses and individual studies highlight associations between elevated state anxiety, depression scores, preoperative pain, diabetes, sleep disturbances, and various other factors with an increased risk of CPSP, with differences observed in prevalence between TKA and THA. While the etiology of CPSP is not fully understood, several factors such as chronic inflammation and preoperative central sensitization have been identified. Other potential mechanisms include genetic factors (e.g., catechol-O-methyltransferase (COMT) and potassium inwardly rectifying channel subfamily J member 6 (KCNJ6) genes), lipid markers, and psychological risk factors (anxiety and depression). With regards to therapeutics and prevention, multimodal pharmacological analgesia, emphasizing nonopioid analgesics like acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs), has gained prominence over epidural analgesia. Nerve blocks and local infiltrative anesthesia have shown mixed results in preventing CPSP. Ketamine, an N-methyl-D-aspartate (NMDA)-receptor antagonist, exhibits antihyperalgesic properties, but its efficacy in reducing CPSP is inconclusive. Lidocaine, an amide-type local anesthetic, shows tentative positive effects on CPSP. Selective serotonin reuptake inhibitors (SSRIs) and serotonin norepinephrine reuptake inhibitors (SNRIs) have mixed results, while gabapentinoids, like gabapentin and pregabalin, present hopeful data but require further research, especially in the context of TKA and THA, to justify their use for CPSP prevention.
Topics: Humans; Arthroplasty, Replacement, Hip; Arthroplasty, Replacement, Knee; Pain, Postoperative; Chronic Pain; Risk Factors; Pain Management; Analgesics
PubMed: 38731944
DOI: 10.3390/ijms25094722 -
International Journal of Molecular... Apr 2024In contrast to cats and dogs, here we report that the α-adrenergic receptor antagonist yohimbine is emetic and corresponding agonists clonidine and dexmedetomidine... (Comparative Study)
Comparative Study
A Comparative Study of the Antiemetic Effects of α-Adrenergic Receptor Agonists Clonidine and Dexmedetomidine against Diverse Emetogens in the Least Shrew () Model of Emesis.
In contrast to cats and dogs, here we report that the α-adrenergic receptor antagonist yohimbine is emetic and corresponding agonists clonidine and dexmedetomidine behave as antiemetics in the least shrew model of vomiting. Yohimbine (0, 0.5, 0.75, 1, 1.5, 2, and 3 mg/kg, i.p.) caused vomiting in shrews in a bell-shaped and dose-dependent manner, with a maximum frequency (0.85 ± 0.22) at 1 mg/kg, which was accompanied by a key central contribution as indicated by increased expression of c-, serotonin and substance P release in the shrew brainstem emetic nuclei. Our comparative study in shrews demonstrates that clonidine (0, 0.1, 1, 5, and 10 mg/kg, i.p.) and dexmedetomidine (0, 0.01, 0.05, and 0.1 mg/kg, i.p.) not only suppress yohimbine (1 mg/kg, i.p.)-evoked vomiting in a dose-dependent manner, but also display broad-spectrum antiemetic effects against diverse well-known emetogens, including 2-Methyl-5-HT, GR73632, McN-A-343, quinpirole, FPL64176, SR141716A, thapsigargin, rolipram, and ZD7288. The antiemetic inhibitory ID values of dexmedetomidine against the evoked emetogens are much lower than those of clonidine. At its antiemetic doses, clonidine decreased shrews' locomotor activity parameters (distance moved and rearing), whereas dexmedetomidine did not do so. The results suggest that dexmedetomidine represents a better candidate for antiemetic potential with advantages over clonidine.
Topics: Animals; Male; Adrenergic alpha-2 Receptor Agonists; Adrenergic alpha-2 Receptor Antagonists; Antiemetics; Clonidine; Dexmedetomidine; Disease Models, Animal; Emetics; Shrews; Vomiting; Yohimbine
PubMed: 38731821
DOI: 10.3390/ijms25094603 -
Cells Apr 2024The antipsychotic drug clozapine demonstrates superior efficacy in treatment-resistant schizophrenia, but its intracellular mode of action is not completely understood....
The antipsychotic drug clozapine demonstrates superior efficacy in treatment-resistant schizophrenia, but its intracellular mode of action is not completely understood. Here, we analysed the effects of clozapine (2.5-20 µM) on metabolic fluxes, cell respiration, and intracellular ATP in human HL60 cells. Some results were confirmed in leukocytes of clozapine-treated patients. Neuroreceptor inhibition under clozapine reduced Akt activation with decreased glucose uptake, thereby inducing ER stress and the unfolded protein response (UPR). Metabolic profiling by liquid-chromatography/mass-spectrometry revealed downregulation of glycolysis and the pentose phosphate pathway, thereby saving glucose to keep the electron transport chain working. Mitochondrial respiration was dampened by upregulation of the F0F1-ATPase inhibitory factor 1 (IF1) leading to 30-40% lower oxygen consumption in HL60 cells. Blocking IF1 expression by cotreatment with epigallocatechin-3-gallate (EGCG) increased apoptosis of HL60 cells. Upregulation of the mitochondrial citrate carrier shifted excess citrate to the cytosol for use in lipogenesis and for storage as triacylglycerol in lipid droplets (LDs). Accordingly, clozapine-treated HL60 cells and leukocytes from clozapine-treated patients contain more LDs than untreated cells. Since mitochondrial disturbances are described in the pathophysiology of schizophrenia, clozapine-induced mitohormesis is an excellent way to escape energy deficits and improve cell survival.
Topics: Humans; Clozapine; Mitochondria; HL-60 Cells; Antipsychotic Agents; Apoptosis; Adenosine Triphosphate; Schizophrenia; Leukocytes; Endoplasmic Reticulum Stress; Cellular Reprogramming; Metabolic Reprogramming
PubMed: 38727298
DOI: 10.3390/cells13090762 -
Journal of the American Heart... May 2024
Topics: Animals; Tryptophan Hydroxylase; Rats; Disease Models, Animal; Pulmonary Arterial Hypertension; Enzyme Inhibitors; Male; Pulmonary Artery; Antihypertensive Agents; Rats, Sprague-Dawley; Hypertension, Pulmonary
PubMed: 38726898
DOI: 10.1161/JAHA.124.034240 -
Nature Jun 2024Psychedelic substances such as lysergic acid diethylamide (LSD) and psilocybin show potential for the treatment of various neuropsychiatric disorders. These compounds...
Psychedelic substances such as lysergic acid diethylamide (LSD) and psilocybin show potential for the treatment of various neuropsychiatric disorders. These compounds are thought to mediate their hallucinogenic and therapeutic effects through the serotonin (5-hydroxytryptamine (5-HT)) receptor 5-HT (ref. ). However, 5-HT also plays a part in the behavioural effects of tryptamine hallucinogens, particularly 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT), a psychedelic found in the toxin of Colorado River toads. Although 5-HT is a validated therapeutic target, little is known about how psychedelics engage 5-HT and which effects are mediated by this receptor. Here we map the molecular underpinnings of 5-MeO-DMT pharmacology through five cryogenic electron microscopy (cryo-EM) structures of 5-HT, systematic medicinal chemistry, receptor mutagenesis and mouse behaviour. Structure-activity relationship analyses of 5-methoxytryptamines at both 5-HT and 5-HT enable the characterization of molecular determinants of 5-HT signalling potency, efficacy and selectivity. Moreover, we contrast the structural interactions and in vitro pharmacology of 5-MeO-DMT and analogues to the pan-serotonergic agonist LSD and clinically used 5-HT agonists. We show that a 5-HT-selective 5-MeO-DMT analogue is devoid of hallucinogenic-like effects while retaining anxiolytic-like and antidepressant-like activity in socially defeated animals. Our studies uncover molecular aspects of 5-HT-targeted psychedelics and therapeutics, which may facilitate the future development of new medications for neuropsychiatric disorders.
Topics: Animals; Humans; Male; Mice; 5-Methoxytryptamine; Anti-Anxiety Agents; Antidepressive Agents; Cryoelectron Microscopy; Hallucinogens; Lysergic Acid Diethylamide; Methoxydimethyltryptamines; Models, Molecular; Receptor, Serotonin, 5-HT1A; Receptor, Serotonin, 5-HT2A; Serotonin Receptor Agonists; Structure-Activity Relationship
PubMed: 38720072
DOI: 10.1038/s41586-024-07403-2 -
Revista Da Associacao Medica Brasileira... 2024Anticipatory nausea and vomiting are unpleasant symptoms observed before undergoing chemotherapy sessions. Less is known about the occurrence of symptoms since the...
OBJECTIVE
Anticipatory nausea and vomiting are unpleasant symptoms observed before undergoing chemotherapy sessions. Less is known about the occurrence of symptoms since the advent of the new neurokinin-1 antagonist.
METHODS
This prospective cohort study was performed at a single Brazilian Institution. This study included breast cancer patients who received doxorubicin and cyclophosphamide chemotherapy and an appropriate antiemetic regimen (dexamethasone 10 mg, palonosetron 0.56 mg, and netupitant 300 mg in the D1 followed by dexamethasone 10 mg 12/12 h in D2 and D4). Patients used a diary to record nausea, vomiting, and use of rescue medication in the first two cycles of treatment. The prevalence of anticipatory nausea and vomiting was assessed before chemotherapy on day 1 of C2.
RESULTS
From August 4, 2020, to August 12, 2021, 60 patients were screened, and 52 patients were enrolled. The mean age was 50.8 (28-69) years, most had stage III (53.8%), and most received chemotherapy with curative intent (94%). During the first cycle, the frequency of overall nausea and vomiting was 67.31%, and that of severe nausea and vomiting (defined as grade>4 on a 10-point visual scale or use of rescue medication) was 55.77%. Ten patients had anticipatory nausea and vomiting (19.23%). The occurrence of nausea and vomiting during C1 was the only statistically significant predictor of anticipatory nausea and vomiting (OR=16, 95%CI 2.4-670.9, p=0.0003).
CONCLUSION
The prevalence of anticipatory nausea is still high in the era of neurokinin-1 antagonists, and failure of antiemetic control in C1 remains the main risk factor. All efforts should be made to control chemotherapy-induced nausea or nausea and vomiting on C1 to avoid anticipatory nausea.
Topics: Humans; Female; Breast Neoplasms; Middle Aged; Prospective Studies; Adult; Antiemetics; Aged; Nausea; Prevalence; Brazil; Antineoplastic Combined Chemotherapy Protocols; Cyclophosphamide; Doxorubicin; Vomiting, Anticipatory; Vomiting; Dexamethasone; Palonosetron
PubMed: 38716933
DOI: 10.1590/1806-9282.20230937 -
Novel 5-HT receptor antagonists modulate intestinal immune responses and reduce severity of colitis.American Journal of Physiology.... Jul 2024Inflammatory bowel disease (IBD) encompasses several debilitating chronic gastrointestinal (GI) inflammatory disorders, including Crohn's disease and ulcerative colitis....
Inflammatory bowel disease (IBD) encompasses several debilitating chronic gastrointestinal (GI) inflammatory disorders, including Crohn's disease and ulcerative colitis. In both conditions, mucosal inflammation is a key clinical presentation associated with altered serotonin (5-hydroxytryptamine or 5-HT) signaling. This altered 5-HT signaling is also found across various animal models of colitis. Of the 14 known receptor subtypes, 5-HT receptor type 7 (5-HT) is one of the most recently discovered. We previously reported that blocking 5-HT signaling with either a selective 5-HT receptor antagonist (SB-269970) or genetic ablation alleviated intestinal inflammation in murine experimental models of colitis. Here, we developed novel antagonists, namely, MC-170073 and MC-230078, which target 5-HT receptors with high selectivity. We also investigated the in vivo efficacy of these antagonists in experimental colitis by using dextran sulfate sodium (DSS) and the transfer of CD4CD45RB T cells to induce intestinal inflammation. Inhibition of 5-HT receptor signaling with the antagonists, MC-170073 and MC-230078, ameliorated intestinal inflammation in both acute and chronic colitis models, which was accompanied by lower histopathological damage and diminished levels of proinflammatory cytokines compared with vehicle-treated controls. Together, the data reveal that the pharmacological inhibition of 5-HT receptors by these selective antagonists ameliorates the severity of colitis across various experimental models and may, in the future, serve as a potential treatment option for patients with IBD. In addition, these findings support that 5-HT is a viable therapeutic target for IBD. This study demonstrates that the novel highly selective 5-HT receptor antagonists, MC-170073 and MC-230078, significantly alleviated the severity of colitis across models of experimental colitis. These findings suggest that inhibition of 5-HT receptor signaling by these new antagonists may serve as an alternative mode of treatment to diminish symptomology in those with inflammatory bowel disease.
Topics: Animals; Receptors, Serotonin; Colitis; Mice; Serotonin Antagonists; Mice, Inbred C57BL; Disease Models, Animal; Dextran Sulfate; Intestinal Mucosa; Signal Transduction; Severity of Illness Index; Colon; Male
PubMed: 38713616
DOI: 10.1152/ajpgi.00299.2023 -
Psychopharmacology Jul 2024Medications are urgently needed to treat symptoms of drug withdrawal and mitigate dysphoria and psychiatric comorbidities that drive opioid abuse and relapse. ITI-333 is...
RATIONALE
Medications are urgently needed to treat symptoms of drug withdrawal and mitigate dysphoria and psychiatric comorbidities that drive opioid abuse and relapse. ITI-333 is a novel molecule in development for treatment of substance use disorders, psychiatric comorbidities, and pain.
OBJECTIVE
Characterize the preclinical profile of ITI-333 using pharmacological, behavioral, and physiological assays.
METHODS
Cell-based assays were used to measure receptor binding and intrinsic efficacy of ITI-333; animal models were employed to assess effects on opioid reinstatement, precipitated oxycodone withdrawal, and drug abuse liability.
RESULTS
In vitro, ITI-333 is a potent 5-HT receptor antagonist (K = 8 nM) and a biased, partial agonist at μ-opioid (MOP) receptors (K = 11 nM; lacking β-arrestin agonism) with lesser antagonist activity at adrenergic α (K = 28 nM) and dopamine D (K = 50 nM) receptors. In vivo, ITI-333 blocks 5-HT receptor-mediated head twitch and MOP receptor-mediated effects on motor hyperactivity in mice. ITI-333 alone is a naloxone-sensitive analgesic (mice) which suppresses somatic signs of naloxone-precipitated oxycodone withdrawal (mice) and heroin cue-induced reinstatement responding without apparent tolerance or physical dependence after chronic dosing (rats). ITI-333 did not acutely impair gastrointestinal or pulmonary function (rats) and was not intravenously self-administered by heroin-maintained rats or rhesus monkeys.
CONCLUSIONS
ITI-333 acts as a potent 5-HT receptor antagonist, as well a biased MOP receptor partial agonist with low intrinsic efficacy. ITI-333 mitigates opioid withdrawal/reinstatement, supporting its potential utility as a treatment for OUD.
Topics: Animals; Mice; Male; Substance Withdrawal Syndrome; Rats; Humans; Rats, Sprague-Dawley; Receptors, Opioid, mu; Serotonin 5-HT2 Receptor Antagonists; Substance-Related Disorders; Opioid-Related Disorders; Dose-Response Relationship, Drug; Oxycodone; Analgesics, Opioid; Self Administration; Cricetulus; CHO Cells
PubMed: 38710856
DOI: 10.1007/s00213-024-06578-w -
Drug Design, Development and Therapy 2024Ondansetron reduces the median effective dose (ED50) of prophylactic phenylephrine to prevent spinal-induced hypotension (SIH) during cesarean delivery. However, the... (Randomized Controlled Trial)
Randomized Controlled Trial
Dose-Response Study of Phenylephrine for Preventing Spinal-Induced Hypotension During Cesarean Delivery with Combined Spinal-Epidural Anesthesia Under the Effect of Prophylactic Intravenous Ondansetron.
BACKGROUND
Ondansetron reduces the median effective dose (ED50) of prophylactic phenylephrine to prevent spinal-induced hypotension (SIH) during cesarean delivery. However, the exact dose response of phenylephrine in combination with prophylactic ondansetron for preventing SIH is unknown. Therefore, this study aimed to determine the dose-response of phenylephrine to prevent SIH in cesarean delivery when 4 mg of ondansetron was used as a preventive method.
METHODS
A total of 80 parturients were enrolled and divided randomly into four groups (n = 20 in each group) who received either 0.2, 0.3, 0.4, or 0.5 μg/kg/min of prophylactic phenylephrine. Ten minutes before the initiation of spinal induction, 4 mg prophylactic ondansetron was administered. The effective dose of prophylactic phenylephrine was defined as the dose required to prevent hypotension after the period of intrathecal injection and up to neonatal delivery. The ED50 and ED90 of prophylactic phenylephrine and 95% confidence intervals (95% CI) were calculated using probit analysis.
RESULTS
The ED50 and ED90 for prophylactic phenylephrine to prevent SIH were 0.25 (95% CI, 0.15 to 0.30), and 0.45 (95% CI, 0.39 to 0.59) μg/kg/min, respectively. No significant differences were observed in the side effects and neonatal outcomes between the four groups.
CONCLUSION
The administration of 4 mg of prophylactic ondansetron was associated with an ED50 of 0.25 (95% CI, 0.15~0.30) and ED90 of 0.45 (95% CI, 0.39~0.59) μg/kg/min for phenylephrine to prevent SIH.
Topics: Adult; Female; Humans; Pregnancy; Anesthesia, Epidural; Anesthesia, Spinal; Cesarean Section; Dose-Response Relationship, Drug; Hypotension; Ondansetron; Phenylephrine
PubMed: 38707613
DOI: 10.2147/DDDT.S452983