<prompt> The following receptor has an intrinsic ion channelHistamine H1 receptorHistamine H2 receptorAdrenergic alfa receptorGABA-benzodiazepine receptor  <response>: GABA -BDZ receptor is an ion channel receptor , has an intrinsic Cl ion channel opening when a agonist binds to it and causes increase in frequency of channel opening and causes hyperpolarization. KDT 6 e pg 42 