An apparatus comprising: a device for inhibiting the neural activity of a carotid sinus nerve or carotid body of a subject, the device comprising: one or more transducers configured to apply a signal to the CSN or associated carotid body of the subject, optionally at least two such transducers; and a controller coupled to the one or more transducers, the controller controlling the signal to be applied by the one or more transducers, such that the signal inhibits the neural activity of the CSN or carotid body to produce a physiological response in the subject, wherein the physiological response is one or more of the group consisting of: an increase in insulin sensitivity in the subject, an increase in glucose tolerance in the subject, a decrease in plasma glucose concentration, optionally fasting plasma glucose concentration, in the subject, a reduction in subcutaneous fat content in the subject, and a reduction in obesity in the subject; and means to detect one or more physiological parameters in the subject, wherein the one or more detected physiological parameters comprise an action potential or pattern of action potentials in a nerve of the subject, wherein the action potential or pattern of action potentials is associated with a condition associated with an impaired response to glucose. a device for inhibiting the neural activity of a carotid sinus nerve or carotid body of a subject, the device comprising: one or more transducers configured to apply a signal to the CSN or associated carotid body of the subject, optionally at least two such transducers; and a controller coupled to the one or more transducers, the controller controlling the signal to be applied by the one or more transducers, such that the signal inhibits the neural activity of the CSN or carotid body to produce a physiological response in the subject, wherein the physiological response is one or more of the group consisting of: an increase in insulin sensitivity in the subject, an increase in glucose tolerance in the subject, a decrease in plasma glucose concentration, optionally fasting plasma glucose concentration, in the subject, a reduction in subcutaneous fat content in the subject, and a reduction in obesity in the subject; one or more transducers configured to apply a signal to the CSN or associated carotid body of the subject, optionally at least two such transducers; and a controller coupled to the one or more transducers, the controller controlling the signal to be applied by the one or more transducers, such that the signal inhibits the neural activity of the CSN or carotid body to produce a physiological response in the subject, wherein the physiological response is one or more of the group consisting of: an increase in insulin sensitivity in the subject, an increase in glucose tolerance in the subject, a decrease in plasma glucose concentration, optionally fasting plasma glucose concentration, in the subject, a reduction in subcutaneous fat content in the subject, and a reduction in obesity in the subject; and means to detect one or more physiological parameters in the subject, wherein the one or more detected physiological parameters comprise an action potential or pattern of action potentials in a nerve of the subject, wherein the action potential or pattern of action potentials is associated with a condition associated with an impaired response to glucose.