| 1. |
- Nylander, Erik, 1986-
(författare)
-
The effects of growth hormone on opioid-induced toxicity in vitro
- 2019
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- There is an ongoing opioid crisis in the United States that is portrayed by a large number of opioid-related deaths. Many of these cases involve commonly used prescription opioids, such as morphine, oxycodone, fentanyl, and methadone. This is concerning and highlights the problems associated with long-term opioid treatment. In addition to opioid-related deaths, long-term opioid use may impact higher brain functions, such as cognitive function. The cause of cognitive decline following opioid treatment may be associated with increased neuronal cell death, inhibited neurogenesis, and altered volumes of specific brain regions important for cognition. Growth hormone (GH), a pituitary hormone regulated by the hypothalamic somatotropic axis, may counteract several of these effects. The hormone, alongside with its mediator insulin-like growth factor-1 (IGF-1), is associated with pro-cognitive effects and display promising neuroprotective actions in the CNS. The main aim for this thesis was to examine the impact of opioids on cell viability and the potentially protective, restorative, and effects linked to pro-cognitive properties of GH in mixed neuronal cell cultures and cell lines. The results clearly display that specific opioids, such as methadone, decrease cell viability, possibly via negative effects on mitochondrial morphology. GH treatment alleviated the negative effects of methadone in cortical cell cultures as well as successfully restored mitochondrial and membrane integrity past injury. Moreover, GH treatment to primary hippocampal cell cultures increased the number of dendritic spines, which are linked to higher cognitive functions, indicating that the hormone act as a cognitive enhancer in the CNS. In conclusion, this thesis provides further evidence that opioids negatively impact cell viability, an effect that may underlie reduced cognitive function as seen in several patients consuming opioids-long term. GH was able to counteract these effects and also able to restore damaged cellular functions. This thesis further confirms the essential role of GH in acting as a cognitive enhancer in the CNS, highlighting the potential role of GH as a treatment for cognitive dysfunctions.
|
|
| 2. |
- Hallberg, Mathias, 1971-
(författare)
-
Anabolic Androgenic Steroids : Effects on Neuropeptide Systems in the Rat Brain
- 2005
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Anabolic-androgenic steroids (AAS) have been used in clinics for decades. The misuse of AAS has previously been attributed merely to sport athletes, taking AAS with intentions to increase muscle mass, enhance physical performance and to improve results in competitions. Today, the misuse of AAS has spread to adolescents and young adults not connected to sports. Alarmingly, many reports are pointing at severe psychiatric adverse effects among AAS abusers, which include mood swings, mania, anxiety, depression and aggression. Numerous examples of severe and often unprovoked violence and brutal crimes have been connected to AAS abuse and there is a strong need for a better understanding of the underlying biochemical events that might account for the adverse behaviors induced by AAS. The general aim of this thesis was to study the effect of chronic AAS administration on neuropeptide circuits in the rat brain associated with the regulation of rewarding effects, memory, anxiety, depression and aggression, using nandrolone decanoate as a prototype AAS.Results demonstrated that daily administration of AAS to rats in doses comparable to those taken by AAS abusers, in certain brain structures significantly affected, a) the levels of the opioid peptides dynorphin B and Met-enkephalin-Arg6Phe7, b) the levels of the tachykinin substance P (SP), c) the density of the SP neurokinin 1 (NK1) receptor, d) the level of the SP metabolite SP1-7 that frequently exerts opposite effects to SP, e) the SP1-7 generating enzyme substance P endopeptidase (SPE) and finally, f) the levels of the neuropeptide calcitonin gene-related peptide (CGRP) often co-localized with SP. The alterations seen in the levels and activities of these neurochemical components are in many aspects compatible with behaviors typified among AAS abusers.
|
|
| 3. |
- Zelleroth, Sofia, 1990-
(författare)
-
Anabolic Androgenic Steroids : Neurobiological Effects of Nandrolone, Testosterone, Trenbolone, and Stanozolol
- 2022
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The use of anabolic androgenic steroids (AAS) for recreational purposes is a health concern, as long-term AAS-use in supraphysiological doses is associated with severe physical and psychological adverse effects. Several behavioral and cognitive problems are reported after long-term AAS-use, and alterations in brain morphology as well as neurotransmitter systems have been reported. The AAS-induced negative impact on the brain may depend on the type of AAS used, but the rationale behind the adverse effects observed is still not clear.The aim of the present thesis was to investigate the neurobiological impact of supraphysiological doses of structurally diverse AAS; testosterone, nandrolone, stanozolol, and trenbolone, as well as of the prodrugs nandrolone decanoate, testosterone undecanoate, testosterone decanoate, and trenbolone decanoate. Wistar rats were used to study the influence on behavior, effects on the brain, and additional somatic effects. Furthermore, in vitro models of immature and mature primary rat cortical cell cultures were used to examine the potential toxic properties of the AAS administered. In the in vitro studies, nandrolone and trenbolone were identified as the most toxic of the AAS investigated, due to their adverse impact on mitochondrial function, membrane integrity, apoptosis, and neurite outgrowth. In vivo, the AAS demonstrated diverse somatic outcomes affecting body weight development, and organ weights to different degrees. In addition, nandrolone decanoate caused a reduced general activity, an effect possibly induced by increased stress vulnerability and alterations in the oxytocinergic system. Furthermore, nandrolone decanoate induced impaired memory in the novel object recognition test. Overall, nandrolone decanoate was identified as the most harmful steroid investigated due to its prominent impact on body weight development, affecting multiple organs, and being the only AAS causing impaired cognitive function. In conclusion, the structurally different AAS exerted diverse effects on cell viability, neurite development as well as regarding physical impairments and impact on behavior, suggesting that harmful physiological, neurological, and psychological outcomes may be expected after AAS-use. These findings highlight that the severity and type of adverse effects depend on the type of AAS used, which is valuable information to consider in order to provide good healthcare and treatment options to AAS-users.
|
|
