[Analysis of the phenomenon of over-the-counter drug abuse and not controlled herbs trade by polish adolescents: Part I]. / Analiza zjawiska naduzywania przez polska mlodziez leków dostepnych bez recepty i ziól niepodlegajacych kontrolowanemu obrotowi: czesc I.

The phenomenon of stupefying by the use of available over-the-counter drugs (OTC) among adolescents is an essential problem in both Poland and throughout the world. Popular analgesics, cold medicine and antihistamines contain psychedelic substances, such as dextromethorphan (DXM), pseudoephedrine/ephedrine, codeine (methylmorphine), dimenhydrinate, paracetamol (acetaminophren) and others. Cases of fatal addiction to dextromethorphan, one of the active substances contained in medicines, e.g., the common cold, have been reported. The test results cited by the authors clearly indicate that the use of OTC drugs, whose turnover is not controlled is a domain of females. The extent of use of drugs not prescribed by a doctor has remained for many years at a constant level. The most common poisonings with OTC drugs are caused by those that affect the respiratory system or exert analgesic or antipyretic effects. They are also used in attempted suicides, especially among females. Analyzing poisonings caused by OTC medications their seasonality has been observed. Their number increases during spring-autumn. A territorial differentiation in areas of OTC drug trade in terms of their quantities, with the predominance of southern regions is also noted. Intoxication with psychoactive substances causes the deterioration of relations between young people. In the reviewed studies there is no detailed information on the composition of non-prescription medicines. Moreover, young people have easy access to mushroom fungi, growing in nearby forests and meadows that may have hallucinogenic effects and are available in pharmacies and on the Internet. Med Pr 2017;68(3):413-422.

Mechanisms of human motor cortex facilitation induced by subthreshold 5-Hz repetitive transcranial magnetic stimulation.

Our knowledge about the mechanisms of human motor cortex facilitation induced by repetitive transcranial magnetic stimulation (rTMS) is still incomplete. Here we used pharmacological conditioning with carbamazepine, dextrometorphan, lorazepam, and placebo to elucidate the type of plasticity underlying this facilitation, and to probe if mechanisms reminiscent of long-term potentiation are involved. Over the primary motor cortex of 10 healthy subjects, we applied biphasic rTMS pulses of effective posterior current direction in the brain. We used six blocks of 200 pulses at 5-Hz frequency and 90% active motor threshold intensity and controlled for corticospinal excitability changes using motor-evoked potential (MEP) amplitudes and latencies elicited by suprathreshold pulses before, in between, and after rTMS. Target muscle was the dominant abductor digiti minimi muscle; we coregistered the dominant extensor carpi radialis muscle. We found a lasting facilitation induced by this type of rTMS. The GABAergic medication lorazepam and to a lesser extent the ion channel blocker carbamazepine reduced the MEP facilitation after biphasic effective posteriorly oriented rTMS, whereas the N-methyl-d-aspartate receptor-antagonist dextrometorphan had no effect. Our main conclusion is that the mechanism of the facilitation induced by biphasic effective posterior rTMS is more likely posttetanic potentiation than long-term potentiation. Additional findings were prolonged MEP latency under carbamazepine, consistent with sodium channel blockade, and larger MEP amplitudes from extensor carpi radialis under lorazepam, suggesting GABAergic involvement in the center-surround balance of excitability.

Nicotine facilitates reinnervation of phenol-injured perivascular adrenergic nerves in the rat mesenteric resistance artery.

Nicotine has been shown to have neuroprotective and neurotrophic actions in the central nervous system. To elucidate the peripheral neurotrophic effects of nicotine, we determined whether nicotine affected the reinnervation of mesenteric perivascular nerves following a topical phenol treatment. A topical phenol treatment was applied to the superior mesenteric artery proximal to the abdominal aorta in Wistar rats. We examined the immunohistochemistry of the distal small arteries 7 days after the treatment. The topical phenol treatment markedly reduced the density of tyrosine hydroxylase (TH)-LI and calcitonin gene-related peptide (CGRP)-LI fibers in these arteries. The administration of nicotine at a dose of 3 mg/kg/day (1.5 mg/kg/injection, twice a day), but not once a day or its continuous infusion using a mini-pump significantly increased the density of TH-LI nerves without affecting CGRP-LI nerves. A pretreatment with nicotinic acetylcholine receptor antagonists hexamethonium, mecamylamine, and methyllycaconitine, but not dextrometorphan, canceled the TH-LI nerve reinnervation induced by nicotine. Nicotine significantly increased NGF levels in the superior cervical ganglia (SCG) and mesenteric arteries, but not in the dorsal root ganglia, and also up-regulated the expression of NGF receptors (TrkA) in the SCG, which were canceled by hexamethonium. These results suggested that nicotine exhibited neurotrophic effects that facilitated the reinnervation of adrenergic TH-LI nerves by activating α7 nicotinic acetylcholine receptor and NGF in the SCG.