## 4 Discussion
However, it was determined that the liver PON level and liver \(\beta\)-glucosidase leavel increased in the MWM-tested control groups compared to the NT groups, but single-dose and multiple-dose scopolamine administration decreased the liver PON and liver \(\beta\)-glucosidase levels of scopolamine-induced memory impairment rats. An increasing number of studies have shown the association of PON activity with neurodegenerative diseases as multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), AD and Parkinson's disease. In the study investigating the effect of ozone therapy on rats in which a demyelination model (multiple sclerosis model) was created using ethidium bromide, it was determined that PON1 activity in the brain was significantly reduced compared to the control group [27]. [PERSON] et al. (2020) tried to explain the relationship of coleresis species with memory and cognitive disorders in rats with scopolamine-induced Alzheimer's disease. Their studies showed that acetylcholinesteraseoniteserase activity was found to be longer in rats given scopolamine compared to the control animals [28]. The enzymatic changes caused by scopolamine in rats will not fully correspond to human NDs, but the results are interesting when the data are compared with studies on this subject. Oxidative stress is linked to increased motor neuron demyelination and has a role in the pathophysiology of MS [29; 30; 31]. It has been noted that blood PON1 activity and total antioxidant status were low in recurrent-remitting multiple sclerosis (RRMS) patients, although total antioxidant status was high [24; 32]. Another multifactorial neuro-degenerative illness with altered mitochondria and dysfunctional brain cells is ALS [33]. [PERSON] et al. (2006) have shown a significant link between the polymorphisms present in the PON gene and ALS [34]. Dementia is another neurodegenerative disorder characterized by a progressive decline in cognitive function. About 80% of dementia cases identified in elderly populations are related to AD [24]. [PERSON] et al. (2015) report that arylesterase and PON-1 levels were lower in individuals with moderate cognitive impairment (MCI), vascular dementia (VAD), and late-onset AD than in healthy controls [35]. Furthermore, [PERSON] et al. (2017) evaluated the genotype, allele frequency, and activity of PON-1 arylesterase in late-onset AD patients and healthy controls, concluding that PON-1 activity is considerably lower in AD patients than in controls [36]. By comparing the PON-high-density lipoprotein (HDL) enzyme activity in the AD group to that of healthy people, [PERSON] et al. (2002) demonstrated a connection between cholesterol levels and the progression of AD and VAD. In comparison to controls, patients with AD and VAD had considerably higher serum cholesterol levels. When compared to healthy controls, PON-1 HDL-associated activity in AD and VAD patients was significantly lower [37]. Our PON results are partially consistent with the literature, as it was determined that scopolamine administration decreases the liver PON level. Since there is limited information about scopolamine application and examination of \(\beta\)-glucosidase levels, the data obtained in this study made a significant contribution to the literature. Determining the serum and liver \(\beta\)-glucosidase levels for adult rat models of neurodegenerative diseases will be useful as an early marker for potential risk. [PERSON] et al. (2003) performed a similar study to test whether serum levels of cytosolic \(\beta\)-glucosidase are elevated in a young rat model of necrotizing enterocolitis and showed the serum concentration of cytosolic \(\beta\)-glucosidase was found to significantly increase in animal models with ischemia and bowel obstruction [38]. Recently, several studies have shed light on CAs as possible new targets for memory impairment and cognitive problems [39]. Our carbonic anhydrase activity studies showed that the CA activities of adult rats are significantly less than young and middle-aged individuals.