Neuronendocrine Function in Sexually Abused Adolescent Girls

January 18, 2013 · Posted in Neurochemistry · Comment 

sexual abuse

Brooks R. Keeshin from a research group led by Frank Putnam presented a poster at the 2012 meeting of the American Academy of Child and Adolescent Psychiatry (AACAP) on neuroendocrine function in recently sexually abused adolescent girls with and without post-traumatic stress disorder (PTSD). Average age of the girls was 15 and they had experienced the sexual abuse six months to one year before the study. The researchers found that morning cortisol awakening response was flattened in the girls, and this was associated with PTSD severity and the severity of intrusive symptoms. Increased adversity prior to the sexual abuse experience was also associated with flattening of the cortisol awakening response.

The researchers suggest that alterations in the hypothalamic pituitary adrenal axis (HPA) appear around the time of the abuse and are associated with the severity of PTSD symptomatology in sexually abused adolescent girls.

Rare Encephalitis Affects NMDA Receptor

October 14, 2011 · Posted in Neurochemistry · Comment 
NMDA

NMDA

At the 57th Annual Meeting of the American Academy of Child and Adolescent Psychiatry (AACAP) in October 2010, Nadine Schwartz reported that in a rare type of encephalitis, antibodies specifically target and bind to N-methyl-D-aspartate (NMDA) receptors, the major receptors for excitatory neurotransmission in the brain. Individuals usually develop psychiatric symptoms before neurological ones, and were previously often thought to be malingering or inventing their illness. Eventually they may develop profound cognitive and motor deterioration and many may require treatment in an intensive care unit in order to provide adequate respiration. Studies show that children with this syndrome appear to respond to anti-immune therapeutic approaches including steroids, plasmaphoresis, and antimetabolites.

Editor’s Note:  The recognition that auto-antibodies can attack the major receptors for excitatory neurotransmission in brain brings to light another potential mechanism that could explain neurochemical dysregulation in the neuropsychiatric disorders.

N-acetylcysteine Affects Electrical Activity in Brain

February 2, 2011 · Posted in Neurochemistry, Potential Treatments · Comment 

At the 65th Annual Scientific Convention of the Society of Biological Psychiatry, researcher Christian Carmeli reported that N-acetylcysteine (NAC, 2 gm/day for six months) increased electroencephalogram (EEG) synchrony over the frontal cortical and left temporal regions in patients with schizophrenia. The EEG measures the frequency and amplitude of electrical activity on both sides of the brain.

N-Acetylcysteine

N-Acetylcysteine

Editor’s note:  These data provide a neurophysiological mechanism that could explain the positive effects of NAC previously observed by researcher Mike Berk and associates in both schizophrenia and bipolar disorders and published in Biological Psychiatry in 2008. NAC is both a glutathione precursor providing antioxidant effects and a modulator of hyper-responsive glutamate reactivity in the n. accumbens or ventral striatum, the reward area of the brain. In placebo-controlled studies NAC appears effective in treating cocaine, heroin, and gambling addiction, as well as trichotillomania (compulsive hair-pulling). These effects are thought to be related to NAC’s dampening of glutamate responses in the n. accumbens, which, along with the dorsal striatum, appears to mediate habit memory. Read more

Episodic vs. Continuous Social Stress Result in Different Rates of Cocaine Use

July 11, 2010 · Posted in Neurochemistry · Comment 

In a study of rodents exposed to stress (by being forced to enter another rodent’s territory) and given the opportunity to self-administer cocaine, those exposed to a few brief episodes of stress increased their cocaine use and engaged in binge-like episodes, while those exposed to stress chronically showed suppressed cocaine use.

At the American College of Neuropsychopharmacology meeting in December 2009, Klaus Miczek and colleagues from Tufts University in Boston presented a fascinating study indicating that the temporal aspects of the experience of social stress may have dramatic impact not only on defeat stress behaviors and the associated biochemistry, but also on the likelihood that an animal adopts cocaine self-administration.  These investigators compared episodic versus chronic defeat stress in rodents.

Episodic social defeat stress consisted of four brief confrontations between an intruding animal and an aggressive resident rat over the course of a period of ten days. In contrast, chronic subordination stress involved the continuous exposure of the intruder rat to an aggressive resident over five weeks, during which time the intruder lived in a protective cage within the resident’s home cage.

The episodically defeated intruder rats showed increases in intravenous cocaine self-administration and prolonged binge-like episodes, along with increases in brain-derived neurotropic factor (BDNF), which is necessary for long-term learning and memory, in the midbrain ventral-tegmental area (VTA) and increased dopamine release in the nucleus accumbens, the reward area of the brain.  In contrast, the continuously subordinate rats showed the opposite pattern of suppressed cocaine intake, suppression of dopamine release in the n. accumbens, and reduced BDNF in the VTA.

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