Publications by authors named "Ryan M Heistad"

Using swine as an experimental model, we examined whether the cannabinoid receptors (CB1R and CB2R) modulated vasomotor tone in isolated pial arteries. It was hypothesized that the CB1R would mediate cerebral artery vasorelaxation in an endothelial-dependent manner. First-order pial arteries were isolated from female Landrace pigs (age = 2 months; N = 27) for wire and pressure myography.

View Article and Find Full Text PDF

The influence of a protein is not determined exclusively by its level of expression, but also by its localization within the cell. The literature often refers to the enzyme monoamine oxidase (MAO) as a mitochondrial enzyme, yet there is evidence that mitochondria-independent pools of MAO exist. These pools of MAO could exert distinct influences across physiological as well as pathological phenotypes.

View Article and Find Full Text PDF

The expression of the two isoforms of monoamine oxidase (MAO A and MAO B) is often inferred from proxy measures such as mRNA transcript levels or catalytic activity. Yet the literature is clear that the proportionality of protein, mRNA, and activity does not guarantee that any of these measures can be used as a proxy for any of the others. Here we provide a protocol for the detection of MAO proteins in cell lysates that can be adapted readily to tissue preparations.

View Article and Find Full Text PDF

The pool of β-Amyloid (Aβ) length variants detected in preclinical and clinical Alzheimer disease (AD) samples suggests a diversity of roles for Aβ peptides. We examined how a naturally occurring variant, e.g.

View Article and Find Full Text PDF

Biological sex exerts distinct influences on brain levels of the β-amyloid (Aβ) peptide in both clinical depression and Alzheimer disease (AD), yet studies in animal models focus primarily on males. We examined behavioral 'despair'/depression (using the tail-suspension test) and memory (using the novel object recognition task) in J20 (hAPP) mice. Three month-old male (but not female) J20 mice exhibited less despair-like behavior, but more evidence of cognitive deficits.

View Article and Find Full Text PDF

The serotonin (5-hydroxytryptamine, 5-HT) transporter (5-HTT) gene-linked polymorphic region (5-HTTLPR) is thought to alter 5-HT signaling and contribute to behavioral and cognitive phenotypes in depression as well as Alzheimer disease (AD). We explored how well the short () and long () alleles of the 5-HTTLPR align with serotoninergic indices in 60 autopsied cortical samples from early-onset AD/EOAD and late-onset AD/LOAD donors, and age- and sex-matched controls. Stratifying data by either diagnosis-by-genotype or by sex-by-genotype revealed that the donor's 5-HTTLPR genotype, i.

View Article and Find Full Text PDF

Monoamine oxidase-A (MAO-A) and MAO-B have both been implicated in the pathology of Alzheimer disease (AD). We examined 60 autopsied control and AD donor brain samples to determine how well MAO function aligned with two major risk factors for AD, namely sex and ε4 status. MAO-A activity was increased in AD cortical, but not hippocampal, samples.

View Article and Find Full Text PDF

The APOE ε4 allele was originally reported to contribute to risk of Alzheimer's disease (AD) in women, yet male and female AD patient-derived data are routinely pooled. Histopathological hallmarks of AD include neurofibrillary tangles centered on hyperphosphorylated Tau and plaques composed of the β-amyloid (Aβ) peptide that is derived by sequential secretase-mediated cleavage of the Amyloid Protein Precursor (APP). We chose to examine profiles of Aβ(1-40), Aβ(1-42), and N-truncated (i.

View Article and Find Full Text PDF