Pressor responses of clonidins injected into some prosencephalic areas of conscious rats

The objective of this investigation was to study the effect of clonidine injection into some prosencephalic areas of unanesthetized rats on mean arterial pressure (MAP) and heart rate (HR). Injection of 40 nmol clonidine in 1.0 gama 150 mM NaCl into rhe medial septal area, lateral hypothalamus, lateral preoptic area and lateral ventricle caused the same increase in MAP, 38 ñ 3 to 41 ñ 5 mmHg, and decrease in HR, -65 ñ 10 to -94 ñ 13 bpm (mean ñ SEM, N = 9 to 11 animnals). These results show that clonidine can act on several prosencephalic areas to induce a pressor response in the conscious rat