摘要:

Dihydroergotoxine mesylate (DHET; active substance of Hydergine®) was shown to be a stronger inhibitor of the low-Km than of the high-Km phosphodiesterase (PE) in cat and rat brain homogenates. The inhibition due to DHET was greater when a purified low-Km PE preparation originating from a sonicated pellet (100,000 ¿r) of rat brain tissue was used. The drug alters the kinetic properties of the enzyme, producing a lowering of the negative cooperativity effect. This kind of PE inhibition is of particular importance at normal cellular cAMP levels, but does not interfere with cAMP production by hormonal stimulatio

ISSN:0304-324X    

DOI:10.1159/000212305

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

1 h after intravenous administration, 3H-DH-ergot alkaloids showed maximal uptake in the range of 10-5M in various visceral organs, and of 10-7M in most parts of the CNS of the cat. The clearance function in both groups of tissues was logarithmical linear, the slope of the straight line for the parts of the CNS being considerably flatter. Repeated administration of these drugs demonstrated a higher retention in the CNS than in the other organs. The single-dose level in the CNS is reinforced and, in contrast to liver and lung, maintained for at least 24 h.

ISSN:0304-324X    

DOI:10.1159/000212306

出版商:S. Karger AG    

年代:1978

数据来源: Karger

摘要:

Iterative transient cerebral ischemic aggressions were produced by interrupting the blood flow in both common carotid arteries for 2 min in unanesthetized cats whose basilar artery has been permanently ligated. The influence of ischemia upon cerebral cortex was assessed by recording electrocortical activity (ECoG), indirect pyramidal tract response (I) and thalamic (nucleus ventralis posterior lateralis) evoked potentials induced by electrical stimulation of the contralateral forelimb. In control animals, the repetition of ischemic episodes delayed the recovery of the indirect pyramidal tract response, demonstrating an impairment of cortical excitability. Otherwise, cerebral ischemia induced an increase of thalamic-evoked responses. This phenomenon appears to result from the suppression of inhibitory corticofugal influence. The effects of dihydroergotoxine mesylate (DHET) upon these responses have been evaluated after intravenous administration (0.05, 0.3 and 0.6 mg/kg). DHET did not significantly modify the disappearance times of the ECoG and of the I cortico-pyramidal response or the recovery delay of the ECoG, but it improved the recovery time of I and inhibited the ischemic increase of the thalamic-evoked potential (0.3 and 0.6 mg/kg). These results suggest that DHET exerts a protective effect on the ischemic cerebral cortex in the experimental conditions used.

ISSN:0304-324X    

DOI:10.1159/000212307

出版商:S. Karger AG    

年代:1978

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212308

出版商:S. Karger AG    

年代:1978

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212309

出版商:S. Karger AG    

年代:1978

数据来源: Karger

ISSN:0304-324X    

DOI:10.1159/000212293

出版商:S. Karger AG    

年代:1978

数据来源: Karger