Table 2 Treatments procedure in experiments 1–6

Experiment 1

ICV Injection

Treatment Groups

A

Control Solution

B

Spexin (5 nmol)

C

Spexin (7.5 nmol)

D

Spexin (10 nmol)

Experiment 2

ICV Injection

Treatment Groups

A

Control Solution

B

β-FNA (µ-opioid receptor antagonist, 5 µg)

C

Spexin (10 nmol)

D

β-FNA + Spexin

Experiment 3

ICV Injection

Treatment Groups

A

Control Solution

B

NTI (δ-opioid receptor antagonist, 5 µg)

C

Spexin (10 nmol)

D

NTI + Spexin

Experiment 4

ICV Injection

Treatment Groups

A

Control Solution

B

nor-BNI (κ-opioid receptor antagonist, 5 µg)

C

Spexin (10 nmol)

D

nor-BNI + Spexin

Experiment 5

ICV Injection

Treatment Groups

A

Control Solution

B

C

SHU9119 (nonselective MC3/MC4 receptor antagonist, 0.5 nmol)

Spexin (10 nmol)

D

SHU9119 + Spexin

Experiment 6

ICV Injection

Treatment Groups

A

Control Solution

B

MCL0020 (selective MC4 receptor antagonist, 0.5 nmol)

C

Spexin (10 nmol)

D

MCL0020 + Spexin