Physiopharmacological interactions between stress hormones and central serotonergic systems

Effect of inflammatory agents on electrical resistance across the blood-brain barrier in pial microvessels of anaesthetized rats.

Neurochemical coupled actions of transmitters in the microvasculature of the brain.

Brain serotonin has been hypothesized to be involved in the modulation of psychotic symptoms in at least some forms of schizophrenia We examined the effects of the serotonin precursor L-5-hydroxytryptophan (5HTP) on D-amphetamine induction of acute psychotic symptoms in schizophrenic patients Preadministration with 5HTP significantly antagonized amphetamine-elicited elevations in thought disturbance, activation, and hallucinations

L-5-hydroxytryptophan attenuates positive psychotic symptoms induced by D-amphetamine.

The central microvasculature consisting of capillaries and pia arachnoid is innervated by adrenergic and peptide neurons acting to regulate local blood flow, promote transport of substances into the brain, control permeability of small molecules and induce metabolism. These processes may be controlled by cyclic AMP and cyclic GMP which are formed from adenylate cyclase and guanylate cyclase upon appropriate neurohumoral stimulation. The sensitivity of the receptors mediating enzyme activation is altered during neuropathological states, namely, hypertension, diabetes, catecholamine depletion, irradiation, stroke, aging and Parkinsonism.

Sandeep K. Agarwal

Papers

Evidence for the lack of serotonergic mechanism in the regulation of blood-brain barrier*