Objective:

2

To investigate the neuromodulatory effect of pinellia total alkaloids (PTA) on the gamma-aminobutyric acidergic (GABAergic) system in epileptic rats

and preliminarily evaluate the anti-epileptic effect of PTA.

Methods:

2

Ninety-one male Sprague-Dawley rats were randomized to a control group (

n

=17) or an epileptic group (

n

=74) using computer-generated random numbers. Status epilepticus (SE) was induced with pilocarpine in the epileptic group. Epileptic rats that survived SE were randomly divided into 4 groups

namely an epilepsy group (

n

=13)

a topiramate (TPM

60 mg/kg) group (

n

=12)

a high-dose PTA (800 mg/kg) group (

n

=12)

and a low-dose PTA (400 mg/kg) group (

n

=10). Treatments were given intragastrically once daily for 14 days. The control group and epilepsy group received normal saline. Spontaneous recurrent seizures (SRSs) were monitored 8-h daily for 7 days after treatment. Then

the hippocampal formation tissues were collected. GABA level was measured using enzyme-linked immunosorbent assay. Protein and mRNA expression levels of glutamate decarboxylase 65 (GAD65)

GABA transporter-1 (GAT-1)

GABA transaminase (GABA-T)

and GABA

A

receptor (GABA

A

R) α4

α5

γ2 and δ subunits were measured using Western-blotting analysis and quantitative polymerase chain reaction.

Results:

2

PTA lowered the incidence and frequency of SRS (both doses vs. the TPM group

P

>

0.05). Compared with the epilepsy group

PTA increased the levels of GABA (both doses

P

<

0.01) and GAD65 (mRNA

800 mg/kg

P

<

0.01)

and suppressed the levels of GAT-1 (mRNA

800 mg/kg

P

<

0.01; 400 mg/kg

P

<

0.05)

GABA-T (mRNA

both doses

P

<

0.01)

and GABA

A

R δ subunit (protein

800 mg/kg

P

<

0.05) and γ2 subunit (protein

both doses

P

<

0.01). PTA upregulated the low-expressed mRNA levels of GABAAR α5 subunit (400 mg/kg

P

<

0.01)

δ subunit (800 mg/kg

P

<

0.05)

and γ2 subunit (400 mg/kg

P

<

0.05).

Conclusions:

2

PTA regulated the GABAergic system through modulating GABA levels and the expression levels of GAD65

GAT-1

GABA-T

and GABA

A

R α4

α5

γ2 and δ subunits. PTA may exert antiepileptic effects on the pilocarpine-induced epilepsy model.