Cm. Lathers et al., THE EFFECT OF PHENOBARBITAL ON AUTONOMIC FUNCTION AND EPILEPTOGENIC ACTIVITY-INDUCED BY THE HIPPOCAMPAL INJECTION OF PENICILLIN IN CATS, Journal of clinical pharmacology, 33(9), 1993, pp. 837-844
This study addressed whether penicillin-induced epileptiform discharge
s in the right hippocampus produced associated autonomic dysfunction.
The study also examined the effect of phenobarbital on the heart rate
and blood pressure changes that were induced by the epileptiform disch
arges. The delay in onset of epileptiform activity at the site of inje
ction ranged from 1 second to 16 minutes, and consisted of interictal
discharges or ictal discharges. With the onset of epileptiform activit
y, blood pressure and heart rate increased significantly from control
(P < .05). Electrocardiogram alterations included: P-R interval change
s; increased P-wave amplitude; QRS complex changes; T-wave inversion;
and ST elevation. Phenobarbital 20 mg/kg intravenously suppressed the
epileptogenic activity and depressed the blood pressure and heart rate
below control (P < .05). In an additional series of experiments, peni
cillin G injected into the right hippocampus in five cats produced epi
leptiform activity and,increased the blood pressure and the heart rate
significantly from the control (P < .05). Phenobarbital (20 mg/kg, in
travenously, and 40 mg/kg, intravenously) also prevented the penicilli
n-induced epileptiform activity. Phenobarbital (40 mg/kg, intravenousl
y) reversed the effect of penicillin on the blood pressure and heart r
ate, to levels significantly below that of control (P < .05). Phenobar
bital diminished both epileptiform activity and autonomic dysfunction.
The autonomic dysfunction related to epileptiform activity induced by
focal hippocampal administration of penicillin was similar to that in
duced by the intravenous administration of pentylenetetrazol.