Which of the following receptor has an ion channel?

GABA receptors are divided into two main types: GABA A and GABA B. GABA A receptors are ionotropic receptors and, like glycine receptors, are pentameric structures that are selectively permeable to Cl-. GABA B receptors are metabotropic receptors that are selectively activated by the antispastic drug baclofen. These receptors are coupled to G proteins that, depending ontheir cellular location, either inhibit Ca 2+ channels or activate K + channels. Ref: Katzung; 13th edition; Page no: 369