The determination of a brain arteriovenous difference for 3-methoxy-4-hydroxyphenethyleneglycol (MHPG)

The aim of the study was to explore the relation between saliva level of 3-methoxy-4-hydroxy-phenylglycol (MHPG) and a later cognitive decline in non-demented elderly subjects. We have reported that sMHPG in 214 elderly subjects living in the community (age 74.5 ± 5.9 years) was associated with scores on the Mini-Mental State Examination (MMSE) and the Frontal Assessment Battery (FAB) in 2004 to 2006 (Time A). The same cohort underwent these cognitive tests again from 2007 to 2009 (Time B). The cognitive function of the 147 of 214 subjects could be reassessed by the same cognitive tests. The score on the FAB, but not the MMSE, was significantly reduced at Time B (14.6 ± 2.6) compared with that of Time A (15.2 ± 1.9). There was a significant negative correlation between the baseline sMHPG and the changes in the FAB score subtracted from Time B to Time A or the scores on the FAB at Time B in men, but not at Time A. These correlations were not found in women. These data indicate that high sMHPG might be associated with subsequent cognitive decline assessed by the FAB in non-demented elderly men living in the community.

Background: Alteration in noradrenergic regulation as well as alteration in the hypothalamic—pituitary—adrenal (HPA) axis have been associated with opioid dependence and acute abstinence symptoms.

Methods: This double-blind, placebo-controlled study evaluated subjective, physiologic, and biochemical responses to yohimbine (.4 mg/kg, IV) in eight patients receiving methadone and compared results to those from a pool of nine healthy volunteers. All subjects were compared for panic anxiety symptom scale (PASS) scores, systolic and diastolic blood pressure, heart rate, plasma 3-methoxy-4 hydroxyphenethyleneglycol (MHPG), and cortisol.

Results: Yohimbine elicited objective and subjective opioid withdrawal and elevated craving for opioid drugs in methadone patients. Significant yohimbine effects were seen across the combined subject group for PASS, physiologic measures, MHPG, and cortisol. Methadone patients had lower baseline MHPG levels. Methadone group interactions with yohimbine were seen for systolic blood pressure and cortisol levels.

Conclusions: Methadone-maintained patients are sensitive to the postsynaptic effects of noradrenergic-facilitating medications, experiencing greater physiologic and psychological symptoms, including an increase in craving. The effect on cortisol supports the above conclusion and is consistent with HPA axis perturbation in opioid dependence as reported in other studies and extends these observations to stable methadone-maintained patients. Medications that increase synaptic noradrenaline should be used with care in opioid-dependent patients.

We measured plasma free HVA and MHPG in 39 cases of psychosis or mania judged to be caused by antidepressant exacerbation of symptoms. A total of 24 of patients had been receiving selective serotonin reuptake inhibitors (SSRI’s). The SSRI group showed a pattern of increased plasma HVA similar to a comparison group of patients with a psychotic/manic relapse secondary to medication non-compliance.

To access the saliva level of free 3-methoxy-4-hydroxyphenylglycol (MHPG) as a biological index of anxiety disorders, gender- or age-dependent changes in saliva MHPG level in patients with anxiety disorders were investigated. Saliva MHPG levels in 196 normal volunteers (59 male, 137 female) and 42 outpatients with anxiety disorders (20 male, 22 female) at the initial consultation to the hospital were measured by gas chromatography-mass spectrometry. Saliva MHPG levels in patients were higher than those in normal subjects. The increase in saliva MHPG levels in male patients was greater than that in female patients. Age-associated increase in the saliva MHPG level was greater in patients than in normal subjects. Especially, a significant interaction of age vs. patient effect was found in female subjects (P=0.0005), but not in male subjects (P=0.174). These data indicate that the measurement of saliva MHPG would be valuable for detecting pathological anxiety in male patients regardless of age and in older female patients, but not in younger female patients.

Background: This study investigated the effects of catecholamine depletion with alpha-methylparatyrosine (AMPT) on mood indices in patients with bipolar disorder who were in long-term remission with lithium therapy.

Methods: Eight subjects with DSM-IV bipolar disorder currently in remission for >3 months on lithium were included in the study. Subjects were given either AMPT or placebo, in a randomized double-blind manner, in two test sessions of 4 days each.

Results: Subjects did not have any significant changes in mood during AMPT or placebo administration; however, 24–48 hours after the last active AMPT dose subjects had a transient relapse of hypomanic symptoms. Relapse of hypomanic symptoms did not correlate with increases in serum levels of homovanillic acid or 3-methoxy-4hydroxyphenylglycol.

Conclusions: These findings suggest that the mechanism of prevention of manic relapse by long-term lithium therapy may be dependent on stability of the catecholamine system.

Plasma homovanillic acid (HVA) has been used as a measure of central dopaminergic activity but the validity of this method continues to be investigated. We used single photon emission tomography (SPECT) assessment of the dopamine (DA) transporter for comparison with plasma HVA in subjects at varying stages of abstinence from cocaine.

Nineteen subjects were studied in two separate treatment sites. Plasma HVA and methoxyhydroxyphenethyleneglycol (MHPG) were measured by gas chromatography-mass spectroscopy (GC-MS). The DA transporter was quantified using the SPECT ligand [¹²³I]BCIT.

At 2 weeks of abstinence and beyond there was an increasing positive correlation between plasma HVA and the SPECT measurement of the DA transporter (V₃″).

Plasma HVA may be more likely to reflect DA transporter density in the striatum when there is not a major drug-related change in the DA system.