Postmortem serotonin (5-HT) concentrations in the cerebrospinal fluid of medicolegal cases

Postmortem chemistry update part II

“…The postmortem 5-HT concentration in cerebrospinal fluid was similar to that described in a previous study carried out by Musshoff et al [151] and higher than the clinical reference value, whereas the postmortem 5-HT level in pericardial fluid overlapped with the clinical serum level. Particularly Table 1 Summary of reports describing postmortem analysis of markers of liver and cardiac function, alcohol misuse, sepsis, inflammation, infection, anaphylaxis, hormones, chromogranin A, and S100B…”

Neuromodulating mice and men: Are there functional species differences in neurotransmitter concentration?

“…A microdialysis study of mouse prefrontal cortex also measured a very low concentration of serotonin (0.21 nM) (de Groote et al, 2002). I was not able to find any microdialysis data on human prefrontal neuromodulator concentration, but a postmortem study of human occipital cortex found a serotonin concentration of approximately 100 nM (Musshoff et al, 2004).…”

“…Rodent microdialysis studies are often done not only in the awake state, but also when the animal is moving about freely (Guiard et al, 2006). Postmortem measurement of neurotransmitter concentrations fails to take into account the dynamics of neurotransmitter regulatory processes, and therefore may not only distort the true in vivo concentrations (Musshoff et al, 2004), but is also problematic for comparison across species. For example, comparing rodent and human postmortem data is problematic because the conditions of death and extracellular fluid collection (Musshoff et al, 2004) are often different across species.…”

“…Postmortem measurement of neurotransmitter concentrations fails to take into account the dynamics of neurotransmitter regulatory processes, and therefore may not only distort the true in vivo concentrations (Musshoff et al, 2004), but is also problematic for comparison across species. For example, comparing rodent and human postmortem data is problematic because the conditions of death and extracellular fluid collection (Musshoff et al, 2004) are often different across species. Microdialysis of in vivo brain cerebrospinal fluid (CSF) is also a more direct measure of brain transmitter concentration than blood, urine, saliva, or even spinal CSF measurement, where these other measurements could also be used to compare species.…”

“…However, if the tonic concentration of transmitter is high enough, it could have a large impact on neurotransmission. One extreme possibility is that with a very high tonic transmitter concentration, such as in the human postmortem study cited earlier (Musshoff et al, 2004), some receptor subtypes are saturated in vivo, resulting in constant activation of that receptor population. Microdialysis studies have shown that behaviorally relevant stimuli such as footshock stress can produce large phasic release of the neuromodulators (Hajos-Korcsok, 2003;Dazzi et al, 2005), which may be another instance in which some receptor subtype populations are saturated with transmitter, albeit transiently.…”