Endogenous melatonin, cortisol, and b-endorphin levels after a marathon

Strenuous exercise increases plasma melatonin, cortisol, and ?-endorphin concentrations. Furthermore, a relationship between endogenous opioids and melatonin has been proposed. We measured plasma melatonin, cortisol, and ?-endorphin in 46 subjects before and after a 28.5-mile high altitude race. Thirteen of the subjects received the orally active opioid antagonist naltrexone immediately before the race. The mean plasma melatonin, cortisol, and ?-endorphin levels were higher after the race than before it; the melatonin results were confirmed by gas chromatography-mass spectrometry assay of 12 subjects. Naltrexone had no effect on the increase in any of the three hormones. (via.)

This study was briefly mentioned in “DMT: The Spirit Molecule.” I happened to run across it and thought I’d tuck it away on the blog in case it ever comes up again for some reason.

Children of Depressed Mothers Have Reduced Muscle Tone at 2 weeks

At two weeks old, researchers found that the children of depressed mothers had decreased muscle tone compared to those born to mothers who weren’t depressed, yet they adjusted more quickly to stimuli like a bell, rattle or light — a sign of neurological maturity.

“It’s difficult to say to what extent these differences are good or bad, or what impact they might have over a longer time frame,” says the study’s lead author, Sheila Marcus, M.D., clinical director of U-M’s Child and Adolescent Psychiatry Section.

“We’re just beginning to look at these differences as part of a whole collection of data points that could be risk markers. These in turn would identify women who need attention during pregnancy or mother/infant pairs who might benefit from postpartum programs known to support healthy infant development through mom/baby relationships.” (via.)

“Exhaustion Syndrome” & Depression

Certain personality traits heighten susceptibility to psychiatric disorders. Therefore a research team at Umeå University wanted to study whether this patient group had any susceptibility factors that could explain the development of their disorder. The patient group is distinguished by being anxious and pessimistic, with a weak sense of self, which is common in many psychiatric disorders. What was special about this group was that they stood out as persistent, ambitious, and pedantic individuals.

Being ambitious, fastidious, and overachieving also appears to make a person more prone to exhaustion syndrome. According to Agneta Sandström’s dissertation, individuals with exhaustion syndrome demonstrate impaired memory and attention capacity as well as reduced brain activity in parts of the frontal lobes. Regulation of the stress hormone cortisol is also impacted in the group, with altered sensitivity in the hypothalamic-pituitary-adrenal axis (HPA axis). [...]

The HPA axis in the patient group shows reduced sensitivity in the pituitary, with less secretion of adrenocorticotropic hormone (ACTH) following stimulation with corticotropin (CRH), as well as heightened sensitivity in the adrenal cortex, with increased release of cortisol in relation to the amount of ACTH secreted. There is also a difference in the diurnal rhythm of cortisol, with the patients presenting a flatter secretion curve than the other two groups. The researchers could not detect any reduction in the volume of the hippocampus in the patient group. The proportion of individuals with measurable levels of the pro-inflammatory cytokine interleukin 1 is higher in the patient group. (via.)

Exercise reverses anxiety phenotype in rats

Exercise can ameliorate anxiety and depression-like behaviours induced by an adverse early-life environment by altering the chemical composition in the hippocampus – the part of the brain that regulates stress response, researchers from UNSW have found. [...]

“What’s exciting about this is that we are able to reverse a behavioural deficit that was caused by a traumatic event early in life, simply through exercise,” said Professor of Pharmacology Margaret Morris, who will present the findings this week at the International Congress of Obesity in Stockholm.

In the study, rats were divided into groups and either isolated from their mothers for controlled periods of time to induce stress or given normal maternal contact. Half were given access to a running wheel.

In addition to being more anxious, animals that were subjected to stress early in life had higher levels of stress hormones and fewer steroid receptors in the part of the brain controlling behaviour.

“Both the anxious behaviour and the levels of hormones in these rats were reversed with access to the exercise wheel,” Professor Morris said.

“We know that exercise can elevate mood, but here we are seeing chemical changes that may underpin this improvement. One of these is increases in brain-derived neurotrophic factor (BDNF), which helps nerve cells grow. (via.)

In other news…
Morphine found to decrease testosterone in the brain, as well as liver, and testis. Which is interesting in light of the fact that a stressed/anxious phenotype of rat would have fewer steroid receptors in their brain.

Robert Sapolsky’s 52 minute Lecture on Depression

This is one of the best videos I’ve ever seen on the physiological roots of depression. This guy (Robert Sapolsky) really goes in-depth and connects the dots between scientific facts and common philosophy & anecdote. 52 minutes — not for the faint of heart.

Creativity, Depression, and DHEAS (a hormone that “blunts the effects of cortisol”)

Well, it turns out the cliché might be true after all: Angst has creative perks. That, at least, is the conclusion of Modupe Akinola, a professor at Columbia Business School, in her paper “The Dark Side of Creativity: Biological Vulnerability and Negative Emotions Lead to Greater Artistic Creativity.” The experiment was simple: She asked subjects to give a short speech about their dream job. The students were randomly assigned to either a positive or negative feedback condition, in which their speech was greeted with smiles and vertical nods (positive) or frowns and horizontal shakes (negative). After the speech was over, the subjects were given glue, paper and colored felt and told to create a collage using the materials. Professional artists then evaluated each collage for creativity.

In addition, Akinola also measured DHEAS (dehydroepiandrosterone), an endogenous hormone that blunts the effects of stress hormones like cortisol. (As I’ve written about before, depression is closely entangled with chronic stress.) Given this chemical power, it’s not surprising that low levels of DHEAS have been associated with susceptibility to volatile mood swings and downward spirals of sadness. Finally, subjects were also asked to self-report their moods, giving the scientists a subjective and objective measurement of how they were feeling, and how the feedback to the speech had shifted their emotional state.

Not surprisingly, positive feedback cheered us up: Participants who received smiles and nods during their speeches reported feeling better than before. Negative feedback had the opposite effect – it’s no fun having our dreams trampled on.

Here’s where things get interesting: People who received negative feedback created better collages, at least when compared to those who received positive feedback or no feedback at all. Furthermore, those with low baselines of DHEAS proved particularly vulnerable to the external effects of frowns, so that they proved to be the most creative of all. (via.)

Other interesting DHEAS tidbits: