Neuropharmacological characterization of local ibogaine effects on dopamine release.
M S Reid, K Hsu, K H Souza, P A Broderick, S P Berger
Journal of neural transmission (Vienna, Austria : 1996) January 1, 1996 DOI: 10.1007/bf01291787 via PubMed
Summary
AI-generated from the abstractIn rats, ibogaine applied directly to the nucleus accumbens or striatum via microdialysis had a biphasic effect on extracellular dopamine: lower doses (10⁻⁶ M–10⁻⁴ M) decreased dopamine levels, while higher doses (5×10⁻⁴ M–10⁻³ M) increased them. The dopamine metabolite DOPAC was unaffected. Co-administration with naloxone or norbinaltorphimine blocked the dopamine decrease, suggesting involvement of kappa opioid receptors. The stimulatory effect at high doses was calcium-independent, not blocked by tetrodotoxin, but reduced by cocaine, reserpine, or alpha-methyl-para-tyrosine pretreatment. In striatal synaptosomes, ibogaine and harmaline inhibited dopamine uptake dose-dependently, indicating the stimulatory effect involves the dopamine transporter.
Study at a glance
| Characteristics | Experimental study Peer reviewed |
|---|---|
| Population | Rats |
| Interventions | Ibogaine Naloxone Norbinaltorphimine Cocaine Reserpine Alpha-methyl-para-tyrosine Harmaline |
| Citations | 19 |
| Key finding | Ibogaine produces a biphasic effect on extracellular dopamine in rat striatum and nucleus accumbens, with lower doses decreasing and higher doses increasing dopamine levels, the former mediated by kappa opioid receptors and the latter by the dopamine transporter. |
Abstract
Local perfusion with ibogaine (10(-6) M-10(-3) M) via microdialysis probes in the nucleus accumbens or striatum of rats produced a biphasic dose-response effect on extracellular dopamine levels. Lower doses (10(-6) M-10(-4) M) produced a decrease while higher doses (5 x 10(-4) M-10(-3) M) produced an increase in dopamine levels. Dihydroxyphenylacetic acid (DOPAC) levels were not effected. Naloxone (10(-6) M) and norbinaltorphimine (10(-6) M-10(-5) M) did not affect dopamine levels, but when co-administered with ibogaine (10(-4) M) blocked the decrease in dopamine levels produced by ibogaine. Ibogaine (10(-3) M) stimulation of dopamine levels in the striatum was calcium independent and not blocked by tetrodotoxin (10(-5) M). Pretreatment with cocaine (15 mg/kg), reserpine (5 mg/kg) or alpha-methyl-para-tyrosine (250 mg/kg) given intraperitoneally significantly reduced ibogaine (10(-3)M) stimulation of striatal dopamine levels. In striatal synaptosomes, both ibogaine and harmaline (10(-7)-10(-4) M) produced dose-dependent inhibition of [3H]-dopamine uptake. These findings suggest that ibogaine has both inhibitory and stimulatory effects on dopamine release at the level of the nerve terminal. It is suggested that the inhibitory effect is mediated by kappa opiate receptors while the stimulatory effect is mediated by interaction with the dopamine uptake transporter.