Blood-brain barrier function following drug-induced hypotension in the dog.
To examine the effects of hypotension induced either with trimethaphan (TMP) or nitroprusside (NTP) on blood-brain barrier (BBB), penetration of Evans blue (EB) was observed in dogs anesthetized with halothane. Dogs given TMP were divided into two groups: Group 1, seven dogs rendered hypotensive to mean cerebral perfusion pressure (CPP) of 45 mmHg for 45 min and then of 30 mmHg for 45 min; Group 2, three dogs examined 3 days after arterial hypotension identical to that in Group 1. Dogs given NTP were divided into four groups: Group 1, seven dogs rendered hypotensive with NTP (at dose less than 1 mg/kg) identical to the TMP-Group 1; Group 2, three dogs examined as the TMP-Group 2; Group 3, seven dogs rendered hypotensive to CPP 45 mmHg for 45 min; Group 4, seven dogs rendered hypotensive with NTP (at dose greater than 1 mg/kg) identical to the NTP-Group 1. In all dogs, the dorsal cortical surface and standardized serial coronal sections were examined for evidence of EB penetration. The mean EB penetration score (+/- SEM) for TMP-Groups 1 and 2 was 12 +/- 6, 0 +/- 0, respectively, and for NTP-Groups 1, 2, 3, and 4 was 105 +/- 14, 30 +/- 7, 6 +/- 6, and 125 +/- 26, respectively. These results suggest that dysfunction of the BBB in the NTP group was more pronounced than in the TMP group.
D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure; D001812:Blood-Brain Barrier / Q000187:drug effects*; D001921:Brain / Q000378:metabolism; D004285:Dogs; D005070:Evans Blue / Q000378:metabolism; D005292:Ferricyanides / Q000494:pharmacology*; D007023:Hypotension, Controlled; D007427:Intracranial Pressure; D009599:Nitroprusside / Q000494:pharmacology*; D014294:Trimethaphan / Q000494:pharmacology*
D005292:Ferricyanides; D009599:Nitroprusside; D005070:Evans Blue; D014294:Trimethaphan