The high pressure neurological syndrome and 2-amino-7-phosphonoheptanoic acid: differences between fed and fasted rats.

The elevated atmospheric pressure at which the main features of the high pressure neurological syndrome (HPNS), i.e. tremor, myoclonus and convulsions, successively appear, have been studied in fed and fasted rats with and without pretreatment with 2-amino-7-phosphonoheptanoic acid (180 mg/kg). The onset pressure for tremor is lower in fasted rats. 2-Amino-7-phosphonoheptanoic acid raises the onset pressure for all three phases of HPNS in fed rats, but only for tremor and convulsions in fasted rats. The results are interpreted in terms of changes in aspartergic and related excitatory neurotransmission.