Not everyone who experiments with cocaine acquires compulsive drug use. The mechanism underlying this individual difference in susceptibility to addiction is poorly understood. Recent studies have... Show moreNot everyone who experiments with cocaine acquires compulsive drug use. The mechanism underlying this individual difference in susceptibility to addiction is poorly understood. Recent studies have identified genes and adverse life events (stress) as risk factors. The objective of this thesis is to investigate the contribution of the adrenal stress hormones glucocorticoids and epinephrine to the psychostimulant effects of cocaine in the inbred DBA/2 and C57BL/6 mouse strains. Behavioural sensitisation, measured as an enhanced locomotor response to repeated cocaine exposure, was used as a model for the long-term neural adaptations underlying aspects of drug addiction. The results demonstrate that adrenal hormones play a critical role in cocaine sensitivity, which depends on genetic background because surgical removal of the adrenals (__adrenalectomy__) prevented cocaine sensitisation in DBA/2, but not C57BL/6 mice. The impact of genetic background was further emphasised by strain-specific changes in the midbrain dopamine system that mediates the rewarding effects of drugs. The effects of adrenalectomy could only be fully reversed by co-administration of glucocorticoids and epinephrine. These findings show that, depending on genetic background, adrenal stress hormones are important risk factors for vulnerability to cocaine, suggesting that pharmacological intervention in stress hormone action has therapeutic potential in drug addiction. Show less
Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary small-vessel disease caused by mutations in the NOTCH3 gene on chromosome 19.... Show moreCerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary small-vessel disease caused by mutations in the NOTCH3 gene on chromosome 19. Magnetic resonance (MR) imaging plays an important role in the diagnostic work-up of CADASIL patients. In this thesis we describe the presence of microbleeds and a new, highly characteristic radiological finding in CADASIL patients, the so called subcortical lacunar lesions (SLL). We describe the natural history of the various brain lesions that can be observed in CADASIL patients, the microbleeds, SLL, lacunar infarcts, and white matter hyperintensities (WMHs). Also included are the results of a study on the differences of the lesions seen in CADASIL as compared to the lesions that occur in multiple sclerosis, a disease with radiological and clinical similarities to CADASIL. We found that MR lesions develop in a predictable way during the course of the disease and that SLL and WMHs in the anterior temporal lobe are helpful radiological hallmarks for the of detection CADASIL. The WMHs in the anterior lobe especially in combination with one of the other CADASIL MR hallmarks should distinguish CADASIL patients from patients with multiple sclerosis. Show less
