RESUMO
In animals, corticotropin-releasing hormone (CRH) has been shown to decrease gastric acid secretion after intracerebral administration. Evidence exists that in man peptides have a direct access to the brain upon intranasal administration. This study aimed at assessing brain-mediated effects of CRH on gastric pH after intranasal administration in humans. Eleven healthy men were tested on 2 occasions in a double-blind within-subject cross-over comparison during treatment with CRH (versus placebo) administered intranasally at a dose of 20 micrograms every 10 min. Gastric pH values were measured continuously by a gastral pH tube. After 2 h of intranasal treatment, 6 micrograms/kg pentagastrin was injected subcutaneously. The subject's mood was assessed by an adjective list (EWL-N) at the end of each experimental condition. Intranasal CRH increased pH baseline values from (mean +/- SE) 1.70 +/- 0.31 to 2.62 +/- 0.53 (corresponding to 54%), whereas during intranasal treatment with placebo pH values remained unchanged (p < 0.05). After injection of pentagastrin, pH values decreased to 0.73 +/- 0.04 during placebo and to 0.93 +/- 0.14 during CRH treatment (n.s.). During treatment with CRH, subjects felt less tired (p < 0.05) and deactivated (p < 0.05). Plasma cortisol and CRH levels were not affected by intranasal CRH, excluding mediation of the CRH effects via resorption into the bloodstream, and TSH levels were slightly decreased by the end of the treatment. Results confirm the notion of a pathway for CRH from the nose to the brain, initiating, via central nervous mechanisms, inhibition of gastric acid secretion and a change of mood in humans.
