Brain and heart catecholamine levels afterl-Dopa administration in reserpine treated mice: Correlations with a conditioned avoidance response
✍ Scribed by Lewis S. Seiden; Arvid Carlsson
- Publisher
- Springer
- Year
- 1964
- Tongue
- English
- Weight
- 227 KB
- Volume
- 5
- Category
- Article
- ISSN
- 0033-3158
No coin nor oath required. For personal study only.
✦ Synopsis
In a previous paper we (SEINES and CAgLSSON 1963) have found that a single injection of L-3,4-dihydroxyphenylalanine (L-DOPA) 20 hours after reserpine administration is able to temporarily and partially reverse the reserpine-induced (2.5 mg/kg) suppression of the conditioned avoidance response (CAR) in mice and rats. In this study a partial recovery of the CAR was observed in mice during the 15--5 5 min interval following the injection of L-DOPA (400 mg/kg). When the mice were tested during the 180--200 rain intervM following the injection the reserpine-induced suppression of the CAR had returned. Since L-DOPA is the metabolic precursor of 3-hydroxytyramine (dopamine, DA) which can be hydroxylated on the beta carbon to yield noradrenaline (NA), it was of interest to determine the levels of these amines in brain and a peripheral tissue, heart, at various time intervals after a single injection of L-DOPA. The following communication will present the results of such an experiment as well as additional data on the CAE in a group of mice tested during the 60--100 min interval following the L-DOPA injection. Methods Chemical. Forty-five female albino mice (N-MIni =Naval Medical Research Institute) weighing between 20 and 30 g were injected (i. p.) with 2.5 mg/kg of reserpine (Ciba) 20--25 hours prior to an injection (i. p.) of 400 mg/kg of L-DOPA in physiological saline. Following the L-DOPA injection the mice were sacrificed by decapitation at the following times: 5, 10, 15, 25, 30, 35, 45, 60, 90 and 180 rain. Two control groups of five mice received neither reserpine nor L-DOPA and one group received reserpine alone. Five brains and hearts were obtained at each time point. The tissues were pooled and analyzed for NA content according to the method of BE~TLE~, CA~LSSON and ROSENG~EN