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Morfin is a clinically used analgesic drug but also an abusive drug. It has an impact on a wide range of CNS regions (nucleus accumbens, ventral tegmentum, hippocampus, etc.) and affects their functions, e.g. cognitive functions or anxiety. Although the results of so far published studies are often contradictory, the effects on cell death and proliferation in the CNS have been demonstrated. In this work, we focused on how chronic administration of morphine and subsequent withdrawal of this drug affects neurogenesis and neurodegeneration in the rat brain and how it affects some markers involved in the addiction and post-drug-induced condition. We have succeeded in introducing immunohistochemical markers for monitoring neurogenesis (bromodeoxyuridine and doublecortin) and neurodegeneration (Fluoro-Jade C) and for detection of selected neuromodulatory peptides (cholecystokinin and neuropeptide Y). We have found that morphine may influence the process of neurogenesis and neurodegeneration, but its effects differ in different CNS structures (nucleus accumbens, hippocampus, and amygdala). Key words: Morphine, brain, rat, withdrawal syndrom, neurogenesis, neurodegeneration

Morphine is a clinically very important drug from the opioid group that is used for treatment of severe pain because of its strong analgetic effect. Opioid receptors mediating the morphine effect interact with the Gi/o class of trimeric G-proteins. Opioid receptors also occur in heart tissue and morphine can thus potentially exercise its effect on the function of this organ. The major aim of this project was to pursue consequences of long-term treatment with morphine on expression and distribution of selected heterotrimeric G-protein subunits in the rat heart. Potential cardioprotective effects of this drug have also been studied. Laboratory rats of the Wistar strain were treated with morphine (1 mg/kg/day or 10 mg/kg/day) for 10 or 28 days. The control group was treated with saline solution. Prolonged treatment with morphine did not cause any effects on Gs, Gi, Gz, Gq/11, G subunits, but the expression of Go rather decreased. The results of subsequent experiments showed that prolonged administration of high doses of morphine may reduce the area affected by infarction and reduced the frequency of ventricle arrhythmias depending on dose and duration of morphine administration. Key words: morphine, myocardium, opioid receptor, G-protein subunits, infarction.

Our previous report showed that the brain peptide Tyr-MIF-1 (Tyr-Pro-Leu-Gly-NH2) blocks the inhibitory effect of morphine sulfate on E-rosette formation by human peripheral blood lymphocytes (PBL). In this study, additional in vitro effects of Tyr-MIF-1 on human PBL were studied. The percentages of positive cells for CD 2, a sheep erythrocyte receptor, CD 4 and CD 8 were unchanged after incubation of PBL with morphine or morphine plus Tyr-MIF-1. Tyr-MIF-1 was not mitogenic by itself. The addition of Tyr-MIF-1 did not increase the proliferative response of PBL to Con A, although morphine did. Tyr-MIF-1 did not activate PBL to produce IL 2 nor did it affect the production of IL 2 by Con A-stimulated PBL. The results suggest that Tyr-MIF-1 does not directly modulate CD 2, CD 4 and CD 8 expression, does not alter the proliferative response of PBL, and does not affect the production of IL 2.

Treatment of newborn rats with 6-hydroxydopa (6-OHDOPA, 60 μg/g IP) increased the levels of norepinephrine in the adult cerebellum and hindbrain. Concurrent treatment with morphine sulfate (20 μg/g IP) potentiated the response to 6-OHDOPA in the cerebellum and pons-medulla. In addition, increased noradrenergic neurite density in 4 week cerebellar cortex (as observed with histofluorescent staining by glyoxylic acid) suggests that neonatal morphine increased the sprouting of noradrenergic neurons in the 6-OHDOPA treated rats.

In order to demonstrate the influence of morphine on the developmental localization of regenerated noradrenergic fibers in rat cerebellum, a glyoxylic histofluorescent method and radiometric assay for norepinephrine (NE) were utilized. An initial reduction of NE in the cerebellum after 6-hydroxydopa [6-OHDOPA; 60 µg/g intraperitoneally (i.p.)] was followed by a return to control levels at 3 days, and an elevation above control levels at 7 days. The initial rates of recovery of NE in the cerebellum of the 6-OHDOPA group of rats and the group receiving morphine (20 µg/g i.p.) in combination with 6-OHDOPA were identical up to 7 days. However, by 14 days NE content was further elevated in the cerebellum of the morphine+6-OHDOPA group. Histofluorescent microscopic observations of the cerebellar cortex correlated with the biochemical findings. A reduction in cerebellar NE content at 3 days was associated with a reduction in the number of visible histofluorescent fibers in the cerebellar cortex. By 7 days the relative number of fibers in the 6-OHDOPA groups was similar to that seen in the control group, but by 9 days the relative number of fluorescent fibers in the cerebellar cortex was increased above control. By 13 days there was a further increase in the relative number of fluorescent fibers in the cerebellar cortex of the morphine+6-OHDOPA group, as compared to the group treated with 6-OHDOPA alone. These findings provide an anatomic correlate for recovery of noradrenergic fibers after 6-OHDOPA, and demonstrate an action of morphine in enhancing regenerative sprouting.

We have previously reported that morphine induces apoptosis. However, the underlying molecular mechanisms remain to be elucidated. Toll-like receptor 2 (TLR2), a key immune receptor in the TLR family, modulates cell survival and cell death in various systems. Evidence indicates that β-arrestin 2 acts as a negative regulator of innate immune activation by TLRs. Here, we investigated the roles of TLR2, the downstreaming mediator MyD88, and β-arrestin 2 in morphine-induced apoptosis. We showed that overexpression of TLR2 in HEK293 cells caused a significant increase in apoptosis after morphine treatment. Inhibition of MyD88 by transfecting dominant negative MyD88 or overexpression of β-arrestin 2 by transfecting β-arrestin 2 full length plasmid in TLR2 overexpressing HEK293 cells attenuated morphine-induced apoptosis. Our study thus demonstrates that TLR2 signaling mediates the morphine-induced apoptosis, and β-arrestin 2 is a negative regulator in morphine-induced, TLR2-mediated apoptosis.

Opiates have been shown to inhibit cell growth and trigger apoptosis, but the underlying molecular mechanisms remain unclear. We have previously shown that morphine induces Fas expression and promotes Fas-mediated apoptosis. Here, we investigated the mechanisms by which morphine modulates apoptosis in human Jurkat cells. Morphine-induced apoptosis was inhibited by transfection with a dominant negative Fas-associated death domain (FADD) plasmid, revealing that morphine-induced apoptosis is dependent on FADD. Furthermore, suppression of endogenous p53 expression by RNA interference technology considerably attenuated the morphine-induced apoptosis. In addition, morphine-induced apoptosis seems to be dependent on the activation of phosphatidylinositol 3-kinase (PI3K), as PI3K inhibition by the PI3K inhibitor LY294002 significantly enhanced morphine-induced apoptosis. Moreover, inhibition of Akt or nuclear factor-kappaB (NF-κB) expression by RNA interference technology also dramatically increased morphine-induced apoptosis. Our study thus demonstrates that morphine induces Jurkat cell apoptosis through FADD/p53, anti-apoptotic PI3K/Akt and NF-κB pathways.

Neonatal Abstinence Syndrome (NAS) is the condition which occurs when newborn babies experience withdrawal symptoms from medications taken by their mothers during pregnancy. Prior research suggest NAS is associated with long-term educational difficulties and alterations in neonatal brain structure. Between 2008 and 2017, NAS rates more than tripled in the United States. An epicenter of the NAS epidemic is Southern Appalachia. West Virginia, the only state with all counties located in Southern Appalachia, has an NAS rate roughly seven times the national average, and in 2017, four of the 10 states with the highest NAS rates were part of Southern Appalachia. Upon reviewing Tennessee data, it was noted that increasing NAS rates had a similar curve to buprenorphine prescribing patterns. Buprenorphine is an opioid partial-agonist prescribed in medication assisted therapy (MAT) intended to help individuals, including those pregnant, avoid withdrawal symptoms. Previous research at an East Tennessee clinic identified buprenorphine in urine drug screens of 16% of all pregnant patients; patients admit to both prescribed and illicit use, including snorting, smoking, and injecting. These findings align with a 2017 study suggesting that mothers of NAS infants in eastern Tennessee, compared to mothers across the state, were more likely to use substances prescribed to another person. Despite the drug’s increasing prescribing patterns and popularity for illicit use, its effects on the mother and fetus remain controversial. We therefore felt it appropriate to investigate possible linkages between buprenorphine prescriptions and NAS rates. For the purposes of this study, we define Southern Appalachia as 250 counties from 7 states, including Tennessee, West Virginia, Virginia, North Carolina, Kentucky, Ohio, and Maryland. Annual NAS rates, buprenorphine prescription rates, drug-induced death rates, and opioid prescribing rates from each county in the region were assessed for the years 2008-2018 using data provided by governmental agencies. It was found that buprenorphine prescriptions in the region more than quintupled between 2008 and 2018. NAS rates and drug-induced death rates did not decrease as well; unfortunately, they dramatically increased. We identified a significant linear association between the rate of NAS diagnoses and buprenorphine prescriptions (r = 0.9774, R2 = 0.9553, p-value less than 0.001) and between the rate of buprenorphine prescriptions and drug-induced deaths (r = 0.7129, R2 = 0.5082, p-value .0311). This is the first report which documents a relationship between NAS rates and increasing buprenorphine prescribing. Discussions regarding current policies for buprenorphine management during pregnancy are warranted. We encourage further research on establishing the lowest effective buprenorphine dose for each patient, and we support the CDC’s resumption of tracking the morphine milligram equivalents (MME) of buprenorphine prescribed during pregnancy so that researchers can further study the effect of congenital MME exposure on fetal outcomes.

The aim of this diploma thesis is to study the effect of morphine withdrawal on catecholaminergic and serotonergic neurotransmitter system in rat brain. Theoretical part of this thesis summarizes basic information known about principles of neurotransmission with focus on the catecholaminergic and serotonergic system, metabolism of its components, their signaling, relevant receptors, their distribution, and especially their effect on morphine dependence and subsequent withdrawal. It also summarizes briefly principles of opioid signaling and outlines the findings yet known about neurochemical analysis of the transmitter systems mentioned above. Experimental part of this thesis is focused on the optimization of the method of high performance liquid chromatography with fluorescence detection and its subsequent use to determine basic components of catecholaminergic and serotonergic neurotransmitter system in samples of different part of brain of rats affected by intraperitoneal administration of morphine sulphate, and its subsequent withdrawal and correspondings unaffected control rats. The expression of selected catecholaminergic receptors in identical samples is also detected. This thesis succesfully implements gradient into the originally isocratic method of high performance liquid chromatography...