In vitro response of large colon arterial and venous rings to vasodilating drugs in horses.

Objective: To determine in vitro vasomotor response of equine large colon arterial and venous rings with and without endothelium to vasodilator drugs, including dopamine (DOP), dopexamine (DPX), acepromazine (ACE), isoxsuprine (ISX), and nifedipine (NFP).

Animals: 7 adult horses.

Procedure: Relaxation of large colon arteries and veins in response to vasodilating drugs was determined by measuring the change in tension of vessel rings when exposed to a cumulative concentration range (10(-8) to 10(-4)M) of each drug.

Responses of guinea-pig lung parenchymal strips to tracheobronchial lavage fluid from horses affected with summer pasture-associated obstructive pulmonary disease.

The response of parenchymal strips from guinea-pig lungs to tracheobronchial lavage fluid (TBLF) collected from 8 normal horses and from 8 affected with summer pasture-associated obstructive pulmonary disease (SPAOPD) was determined. TBLF was collected during the summer (July) and winter (February) seasons. The serum/TBLF urea nitrogen ratio was used to standardize the mediator concentration in the TBLF.

Involvement of nitric oxide in the mediation of NANC inhibitory neurotransmission of guinea-pig trachea.

1. The involvement of nitric oxide (NO) in the non-adrenergic non-cholinergic inhibitory (NANC-i) neurotransmission was evaluated in guinea-pigs anaesthetized with chloralose-urethane, using a tracheal pouch preparation. 2.

Biphasic responses of equine colonic vessel rings to vasoactive inflammatory mediators.

1. The role of endothelium in modulating equine colonic vessel responses to histamine (HST), 5-hydroxytryptamine (5-HT), bradykinin (BK) and acetylcholine (ACh) was evaluated in vitro. 2.

Sedative and analgesic effects of medetomidine in beagle dogs infected and uninfected with heartworm.

The sedative and analgesic effects of medetomidine were evaluated in heartworm-infected (HW+) and uninfected (HW-) beagle dogs by intravenous (IV) and intramuscular (IM) administration of 30 micrograms/kg and 40 micrograms/kg doses, respectively. Posture, response to noise and the pedal reflex were monitored. A procedure for mock radiographic positioning was performed to evaluate its overall clinical use.