Abuse of amphetamine-based stimulants is a primary public health concern. Recent studies have underscored a troubling escalation in the inappropriate use of prescription amphetamine-based stimulants. However, the neurophysiological mechanisms underlying the impact of acute methamphetamine exposure (AME) on sleep homeostasis remain to be explored. This study employed non-human primates and electroencephalogram (EEG) sleep staging to evaluate the influence of AME on neural oscillations. The primary focus was on alterations in spindles, delta oscillations, and slow oscillations (SOs) and their interactions as conduits through which AME influences sleep stability. AME predominantly diminishes sleep-spindle waves in the non-rapid eye movement 2 (NREM2) stage, and impacts SOs and delta waves differentially. Furthermore, the competitive relationships between SO/delta waves nesting with sleep spindles were selectively strengthened by methamphetamine. Complexity analysis also revealed that the SO-nested spindles had lost their ability to maintain sleep depth and stability. In summary, this finding could be one of the intrinsic electrophysiological mechanisms by which AME disrupted sleep homeostasis.
Animals ; Methamphetamine ; Electroencephalography ; Male ; Sleep/drug effects* ; Central Nervous System Stimulants ; Delta Rhythm/drug effects* ; Sleep Stages/drug effects*

Gamma band oscillation (GBO) and sensory gating (SG) are associated with many cognitive functions. Ketamine induces deficits of GBO and SG in the prefrontal cortex (PFC). However, the time-courses of the effects of different doses of ketamine on GBO power and SG are poorly understood. Studies have indicated that GBO power and SG have a common substrate for their generation and abnormalities. In this study, we found that (1) ketamine administration increased GBO power in the PFC in rats differently in the low- and high-dose groups; (2) auditory SG was significantly lower than baseline in the 30 mg/kg and 60 mg/kg groups, but not in the 15 mg/kg and 120 mg/kg groups; and (3) changes in SG and basal GBO power were significantly correlated in awake rats. These results indicate a relationship between mechanisms underlying auditory SG and GBO power.
Acoustic Stimulation ; Analysis of Variance ; Animals ; Dose-Response Relationship, Drug ; Electroencephalography ; Excitatory Amino Acid Antagonists ; pharmacology ; Gamma Rhythm ; drug effects ; Ketamine ; pharmacology ; Male ; Prefrontal Cortex ; drug effects ; Rats ; Rats, Sprague-Dawley ; Sensory Gating ; drug effects ; Sleep Stages ; drug effects ; Statistics as Topic ; Time Factors ; Wakefulness ; drug effects

Codeine is widely prescribed in clinical settings for the relief of pain and non-productive coughs. Common adverse drug reactions to codeine include constipation, euphoria, nausea, and drowsiness. However, there have been few reports of serious adverse reactions after codeine ingestion in adults. Here, we present a case of severe anaphylaxis after oral ingestion of a therapeutic dose of codeine. A 30-year-old Korean woman complained of the sudden onset of dyspnea, urticaria, chest tightness, and dizziness 10 minutes after taking a 10-mg dose of codeine to treat a chronic cough following a viral infection. She had previously experienced episodes of asthma exacerbation following upper respiratory infections, and had non-atopic rhinitis and a food allergy to seafood. A skin prick test showed a positive response to 1-10 mg/mL of codeine extract, with a mean wheal size of 3.5 mm, while negative results were obtained in 3 healthy adult controls. A basophil histamine release test showed a notable dose-dependent increase in histamine following serial incubations with codeine phosphate, while there were minimal changes in the healthy controls. Following a CYP2D6 genotype analysis, the patient was found to have the CYP2D6*1/*10 allele, indicating she was an intermediate metabolizer. An open label oral challenge test was positive. To the best of our knowledge, this is the first report of a patient presenting with severe anaphylaxis after the ingestion of a therapeutic dose of codeine, which may be mediated by the direct release of histamine by basophils following exposure to codeine.
Adult ; Alleles ; Anaphylaxis* ; Asthma ; Basophil Degranulation Test ; Basophils ; Codeine* ; Constipation ; Cough ; Cytochrome P-450 CYP2D6 ; Dizziness ; Drug-Related Side Effects and Adverse Reactions ; Dyspnea ; Eating ; Euphoria ; Female ; Food Hypersensitivity ; Genotype ; Histamine ; Histamine Release ; Humans ; Nausea ; Respiratory Tract Infections ; Rhinitis ; Seafood ; Skin ; Sleep Stages ; Thorax ; Urticaria

Nefopam (NFP) is a non-opioid, non-steroidal, centrally acting analgesic drug that is derivative of the non-sedative benzoxazocine, developed and known in 1960s as fenazocine. Although the mechanisms of analgesic action of NFP are not well understood, they are similar to those of triple neurotransmitter (serotonin, norepinephrine, and dopamine) reuptake inhibitors and anticonvulsants. It has been used mainly as an analgesic drug for nociceptive pain, as well as a treatment for the prevention of postoperative shivering and hiccups. Based on NFP's mechanisms of analgesic action, it is more suitable for the treatment of neuropathic pain. Intravenous administration of NFP should be given in single doses of 20 mg slowly over 15-20 min or with continuous infusion of 60-120 mg/d to minimize adverse effects, such as nausea, cold sweating, dizziness, tachycardia, or drowsiness. The usual dose of oral administration is three to six times per day totaling 90-180 mg. The ceiling effect of its analgesia is uncertain depending on the mechanism of pain relief. In conclusion, the recently discovered dual analgesic mechanisms of action, namely, a) descending pain modulation by triple neurotransmitter reuptake inhibition similar to antidepressants, and b) inhibition of long-term potentiation mediated by NMDA from the inhibition of calcium influx like gabapentinoid anticonvulsants or blockade of voltage-sensitive sodium channels like carbamazepine, enable NFP to be used as a therapeutic agent to treat neuropathic pain.
Administration, Intravenous ; Administration, Oral ; Analgesia ; Analgesics, Non-Narcotic ; Anticonvulsants ; Antidepressive Agents ; Calcium ; Carbamazepine ; Dizziness ; Drug-Related Side Effects and Adverse Reactions ; Hiccup ; Long-Term Potentiation ; Molecular Mechanisms of Pharmacological Action ; N-Methylaspartate ; Nausea ; Nefopam* ; Neuralgia* ; Neurotransmitter Agents ; Nociceptive Pain ; Norepinephrine ; Shivering ; Sleep Stages ; Sodium Channels ; Sweat ; Sweating ; Tachycardia