The effect of selective opioid receptor agonists and antagonists on epileptiform activity in morphine‐dependent infant mice hippocampal slices

Abstract

Hippocampal slices of mouse brain were used to estimate how selective agonist and antagonist of opioid receptors alter Low-Mg artificial cerebrospinal fluid (LM-ACSF)-induced epileptiform activities in normal and morphine-dependent mice. Brain slices were obtained from control and morphine-dependent mice. The morphine-dependent group received morphine once a day for 5 consecutive days, and the control group received saline. All injections were administered subcutaneously (s.c) in a volume of 0.1mL on postnatal days 14-18. Brain slices were perfused with LM-ACSF along with selective agonist and antagonist of μ, κ and δ opioid receptors. Changes in spike count per unit of time were used as indices to quantify the effects of LM-ACSF exposure in the slices. In both groups, DAMGO (selective μ opioid receptor agonist) and DPDPE (selective δ opioid receptor agonist) suppressed while Dyn-A (selective κ opioid receptor agonist) potentiated the epileptiform activity. Meanwhile, BFN-A (selective μ opioid receptor antagonist) recovered epileptiform activity in normal brain slices but not in morphine-dependent ones. NTI (selective δ opioid receptor antagonist) and nor-BNI (selective κ opioid receptor antagonist) decreased epileptiform activity. It seems that the excitatory effect of morphine on epileptiform activity was mediated through kappa receptors and its inhibitory effect was mediated via the mu receptor and, to a lesser degree, through the delta receptor. The pattern of effect was similar in normal and morphine-dependent slices, but the intensity of the effect was significantly stronger in normal mice. Finding of this study might be considered for further research and attention in epilepsy treatment.

Interactive Effects of Exercise, Sex Hormones, and Transient Congenital Hypothyroidism on Long-Term Potentiation in Hippocampal Slices of Rat Offspring

“…The slices were stored in a brain slice keeper oxygenated with 95% O 2 /5% CO 2 at room temperature for at least one hour before use. After recovery, a single slice was laid in the recording chamber and perfused constantly with ACSF at the rate of 2 mL/minute and at 30–33°C (Panahi et al, 2017). In the current study, one slice per rat was used and recorded successfully.…”

Effects of prenatal methamphetamine exposure on spatial cognition and hippocampal synaptic plasticity in adolescent rats

“…The slices were stored in a brain slice keeper oxygenated with 95% O 2 /5% CO 2 at the room temperature for at least 1 h before use. After recovery, a single slice was laid in the recording chamber and perfused constantly with ACSF at the rate of 2 ml/min and at 30–33°C (Derafshpour et al, 2019; Panahi et al, 2017). In the current study, one slice per rat was used and recorded successfully.…”

The effects of choline supplementation in mothers with hypothyroidism on the alteration of cognitive–behavioral, long‐term potentiation, morphology, and apoptosis in the hippocampus of pre‐pubertal offspring rats

“…After recovery, a single slice was laid in the recording chamber and perfused constantly with ACSF at the rate of 2 mL/min and at 30–33°C. In the current study, one slice per rat was used and recorded successfully (Panahi et al, 2017).…”

“…The slices were stored in a brain slice keeper oxygenated with 95% O 2 /5% CO 2 at room temperature (22-23 C) for at least 1 h before use. After recovery, a single slice was laid in the recording chamber and perfused constantly with ACSF at the rate of 2 mL/min and at 30-33 C. In the current study, one slice per rat was used and recorded successfully (Panahi et al, 2017).…”