Drug targeting to the brain: Transfer of picolinic acid along the olfactory pathways

• Picolinic acid (PA) protects against quinolinic acid- and kainic acid-induced neurotoxicity in the brain. To study the uptake of PA to the brain, we administered [H-3]PA via a unilateral nasal instillation or iv injection to mice. Autoradiography demonstrated a rapid uptake of radioactivity in the olfactory nerve layer and in the ipsilateral olfactory bulb (OB) following nasal instillation of [H-3]PA. After 4h, there was a high level of radioactivity in the central parts of the ipsilateral OB and olfactory peduncle. Moreover, iv injection of [H-3]PA demonstrated a selective uptake and retention of radioactivity in the OB. Gas chromatography-mass spectrometry (GC-MS) demonstrated the presence of PA and PA-glycine conjugate in the OB. In mice with reduced peripheral olfactory innervations there was a decreased uptake of [H-3]PA in the OB as compared to controls suggesting that an intact olfactory neuroepithelium, is a prerequisite for an uptake of PA to the OB. There is an increased interest in brain targeting of drugs with limited ability to pass the blood-brain barrier. The present results demonstrate that PA fulfils structural requirements for a transfer along the olfactory pathways to the brain.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Hälsovetenskap -- Arbetsmedicin och miljömedicin (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Health Sciences -- Occupational Health and Environmental Health (hsv//eng)

Keyword

olfactory system

picolinic acid

intranasal instillation

autoradiography

Publication and Content Type

art (subject category)

ref (subject category)