Cardiovascular and Sympathetic Effects of 1-O-Hexadecyl-2-Acetyl-sn-Glycero-3-Phosphocholine in Conscious Shr and Wky Rats

Abstract

Injections of 1-O-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine (alkylacetyl-GPC, 0.2-5.0 nmol/300 g body wt) induced dose-related hypotension and tachycardia in spontaneous hypertensive (SHR) and normotensive control (WKY) rats. The hypotension that developed was more pronounced in SHR than in WKY rats and was unchanged by indomethacin pretreatment. Plasma norepinephrine (NE) and epinephrine (EPI) levels were markedly increased at the time of maximal hypotension (2 min after injection of alkylacetyl-GPC); plasma EPI (but not NE) was higher in the SHR than in WKY animals. Plasma levels of TXB2 [thromboxane B2], but not 6-keto-PG[prostaglandin]F1.alpha., increased in both groups; the increase was more pronounced in SHR than in WKY rats. In pithed SHR rats, alkylacetyl-GPC caused only short-lasting hypotension, without any effect on heart rate or circulating levels of NE or EPI. Apparently, there is an increased vascular sensitivity to alkylacetyl-GPC in SHR rats and activation of TX-generating elements in both SHR and WKY rats.